diff --git a/CHANGELOG.md b/CHANGELOG.md
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,4 +1,76 @@
 
+50200.10.0
+==========
+
+New features:
+ * Per-channel notification settings for non-DM channels can now be
+   managed with the `/notify-prefs` command. As part of that change,
+   themes got a new attribute, `brickForm.focusedInput`, that governs
+   how focused form inputs are styled. (Thanks to Isaiah Mindich for
+   this feature)
+ * A new configuration file setting, `messageSelectAfterURLOpen`, was
+   added to govern how URL opening works in message selection mode. When
+   `False` (the default), opening URLs from a selected message returns
+   the application to the main UI (the behavior prior to this release).
+   When `True`, opening URLs leaves the application in message selection
+   mode, allowing the user to continue opening URLs from other messages
+   before returning to main mode manually.
+ * The message viewing window now supports paging horizontally. This
+   change adds two new key events:
+    * `page-left` with default binding `Shift-Left`
+    * `page-right` with default binding: `Shift-Right`
+ * Matterhorn now sets the terminal window title based on unread
+   activity (`matterhorn*` when there are unread messages; `matterhorn`
+   otherwise.)
+ * The `/theme` command now opens an interactive theme list window to
+   choose between available built-in themes.
+ * Added support for handling muted channels and respecting the `/mute`
+   server command (thanks to Isaiah Mindich for this feature)
+ * Make `Shift-Home`, not `Home`, selected the oldest message when in
+   normal mode (#258). This change:
+    * Changes the default keybinding for entering message selection mode
+      and selecting the oldest message from `Home` to `Shift-Home`.
+    * Adds a new key event, `select-oldest-message`, that `Shift-Home`
+      triggers by default.
+    * `Home` now triggers the `editor-home` event. Users wanting the
+      old behavior can simply unbind the `editor-home` key event and
+      bind `select-oldest-message` to `Home`.
+ * New 256-color variants of the built-in light and dark themes were
+   added. Those themes are identical to the 16-color variants except
+   that larger pools of 256-color values are used to assign colors
+   to usernames. If a username color chosen by the new themes is
+   objectionable, it can be customized by first using the new
+   `/username-attribute` command to find out which attribute is used
+   to render a username and then setting it in the theme customization
+   config. As part of this change the number of theme attributes for
+   usernames was extended to 50, meaning attributes from `username.0` to
+   `username.49` now govern the assignment of colors.
+
+Other improvements:
+ * The `/members` window now displays the total server user count in
+   the title bar to avoid confusion about the number of displayed search
+   results, which is capped by the server's API response.
+ * Autocompletion now completes `@all` and `@channel` with prefix
+   matches only and puts them after all other alternatives in the
+   alternative list.
+ * The help documentation on themes now documents the `#RRGGBB` theme
+   color syntax that was already supported but not documented.
+ * Key events now supported in the attachment management UI are now
+   included in the keybinding help list.
+ * The help documentation on themes now shows an attribute demo for each
+   theme attribute using the current theme's colors.
+ * Some documentation in the `README` was factored out into other
+   documents in `docs/`.
+ * The UI for showing typing notifications was improved.
+ * The `/leave` command now hide DM and group channels instead of
+   reporting an error (#626)
+
+Bug fixes:
+ * Matterhorn now properly restores the terminal state before crashing
+   with unhandled exceptions (#622)
+ * The URL list accessible with `C-o` now shows URLs from messages
+   regardless of what kind of user reference they contain (#638)
+
 50200.9.0
 =========
 
diff --git a/README.md b/README.md
--- a/README.md
+++ b/README.md
@@ -7,19 +7,6 @@
 
 ![](screenshots/screenshot-00.png)
 
-# New Release Notifications
-
-Get notified about new Matterhorn releases by following our Twitter account!
-
-[https://twitter.com/matterhorn_chat](https://twitter.com/matterhorn_chat)
-
-# Chat With the Developers
-
-The Matterhorn developers hang out on the official Mattermost
-community server. Stop by to get support and say hello!
-
-[https://community.mattermost.com/core/channels/matterhorn](https://community.mattermost.com/core/channels/matterhorn)
-
 # Quick Start
 
 We provide pre-built binary releases for some platforms. Please see the
@@ -45,183 +32,18 @@
 would download matterhorn version `30600.2.4`. See [Our Versioning
 Scheme](#our-versioning-scheme) for details.
 
-# Authentication
-
-`matterhorn` supports username/password authentication as well as
-authentication by Personal Access Token or session token. The following
-subsections provide details on using each method.
-
-## Username / Password Authentication
-
-Matterhorn's start-up login user interface will allow you to provide
-a username and password for authentication. We recommend that you
-put the username in your Matterhorn configuration file and configure
-Matterhorn to obtain your password from your system keychain. See the
-`docs/sample-config.ini` file for documentation on the `user` and
-`passcmd` settings, respectively.
-
-## Personal Access Token Authentication
-
-Matterhorn's start-up login user interface will also allow you to
-provide an session or Personal Access Token. If a token is provided, it
-will take precedence over a username and password.
-
-We recommend Personal Access Tokens because they don't expire except
-when revoked. To use a Personal Access Token:
-
-* Ask your Mattermost server administrator to enable Personal Access
-  Tokens on your Mattermost account.
-* Create a Personal Access Token.
-* Add the new token to your system keychain. (Details on how to do this
-  depend on your platform.)
-* Configure Matterhorn's `tokencmd` configuration option to query the
-  system keychain to get the token. See `docs/sample-config.ini` for
-  examples of how to do this with `passcmd` and `tokencmd`.
-
-The steps for configuring Personal Access Tokens can be found in [the
-Mattermost documentation](https://docs.mattermost.com/developer/personal-access-tokens.html).
-
-## Token Cookie Authentication
-
-If your server does not support username and password authentication
-(e.g. if GitLab authentication is the only supported method), you can
-use your browser client's token cookie to authenticate:
-
-* Authenticate to GitLab (or other identity provider) using the
-  Mattermost web client.
-* Once your browser has returned to the Mattermost interace, obtain the
-  value of the `MMAUTHTOKEN` browser cookie.
-* Start Matterhorn and enter the value of the `MMAUTHTOKEN` token in the
-  login interface field labeled `Access token:` or add the token to the
-  system keychain as described above.
-
-Please note that unlike a Personal Access Token, the web client's token
-cookie will expire, so these steps will need to be repeated each time
-you log in with Matterhorn. As a result, we strongly recommend the use
-of a Personal Access Token instead if at all possible.
-
-Firefox users: you might consider using the
-[mattermost-session-cookie-firefox](https://github.com/ftilde/mattermost-session-cookie-firefox)
-script to make this process easier.
-
-# Configuring
-
-For configuration options you have two choices:
-
-* Interactive configuration entered on each program run
-* Configuration via stored settings in a config file
-
-The first option is useful when trying out the program because you can
-get up and running without worrying about making a configuration. Once
-you're ready to make your settings persistent, they can be added to
-a configuration file. An example configuration file can be found at
-`docs/sample-config.ini`. Any settings omitted from the configuration
-will be obtained interactively at startup.
-
-When looking for configuration files, matterhorn will prefer
-`config.ini` in the current working directory, but will look in the
-typical XDG configuration directories (you'll probably want to use
-`$HOME/.config/matterhorn/config.ini`) and as a last resort look for a
-globally-accessible `/etc/matterhorn/config.ini`.
-
-# Using the Client
-
-The user interface has three main areas:
-
-* Left: list of channels you're in, and list of users in your team and
-  their statuses (`+` means online, `-` means away, `×` means Do Not
-  Disturb, and an absent sigil means offline)
-* Right: messages in the current channel
-* Bottom: editing area for writing, editing, and replying to messages
-
-You can use built-in keybindings or `/cmd`-style commands to operate the
-client. Keybinding and command help may be obtained in a number of ways:
-
-* The `/help` command within Matterhorn.
-* The `F1` key within Matterhorn.
-* Running matterhorn with the `-k` or `-m` arguments to get a text table of available keybindings or commands respectively.
-* Running matterhorn with the `-k` or `-m` arguments with `-f markdown` to get a [Markdown table of available keybindings](docs/keybindings.md) or [Markdown table of available commands](docs/commands.md).
-
-    Note: The keyboard and command output commands do not start the
-    client but simply print to stdout and exit. The keybindings shown
-    include any user overrides from the config files; use the `-i`
-    flag to skip loading the local config files and see the Matterhorn
-    default keybindings.
-
-Keybindings may include modifiers such as Control (indicated with a
-`C-` prefix) or Meta (indicated with a `M-` prefix). If your keyboard
-has an `Alt` key, that will work as `Meta`. If it does not, you may be
-able to configure your terminal to provide `Meta` via other means
-(e.g. iTerm2 on OS X can be configured to make the left Option key
-work as Meta). Keybindings can be customized in the configuration
-file; see `/help keybindings` for details.
-
-To join a channel, use the `/join` command to choose from a list of
-available channels. To create a channel, use `/create-channel`. To leave
-a channel, use `/leave-channel`.
-
-To create a private group chat amongst yourself and other users, use the
-`/group-msg` command, e.g., `/group-msg user1 user2`.
-
-To see the members in the current channel, use the `/members` command.
-
-To send a message, type it into the editor and press Enter to send.
-To send a multi-line message, toggle multi-line mode with the default
-binding `M-e`. Markdown syntax is accepted.
-
-To edit your current message in an external editor (`$EDITOR`), use the
-default binding of `M-k`.
-
-To see a live preview of the message you're about to send while you
-compose it (e.g. to check on how your Markdown syntax will be rendered),
-toggle preview mode with the default binding `M-p`.
-
-To change channels, use `/focus` or one of the default bindings `C-n`
-(next channel), `C-p` (previous channel), `C-g` (fast channel switch).
-
-To directly message another user, use `/focus` or `C-g`.
-
-`C-g` channel switching mode does a substring match of the input text on
-the channel and usernames; metacharacters `^` and `$` at the beginning
-or end of input, respectively, anchor the match in case of multiple
-matches. The cursor in this mode is usable with `C-n` and `C-p`.
-
-To switch to the channel you were in prior to the current channel, use
-the default binding `M-s` (swap). The most recent channel is marked in
-the channel list with a "`<`" indicator.
-
-To switch to the next channel with unread messages, use the default
-binding `M-a`. Pressing `M-a` repeatedly will visit other channels with
-unread messages, and the channel you started in when first pressing
-`M-a` will be marked with `~` in the sidebar. Pressing `M-a` will return
-to that channel after other channels with unread messages have been
-visited.
-
-To quickly show a list of URLs mentioned in the current channel and then
-open one in your local browser, use the default binding of `C-o` and
-configure the `urlOpenCommand` configuration setting.
-
-To edit, delete, flag, or reply to a message, select a message with
-the default binding of `C-s`. Use the default binding of `C-c` to
-cancel these operations.
-
-Messages that have been flagged can be viewed with either the `/flags`
-command or `M-8`. This view allows you to select and unflag particular
-messages, as well.
+# Get Help!
 
-To enable spell-checking in the message editor, install Aspell and set
-`enableAspell` to `True` in your configuration. To override Aspell's
-choice of master dictionary, set the `aspellDictionary` option to the
-name of the dictionary you'd like to use.
+We provide a number of avenues for getting support:
 
-To attach a file to the post being edited, use the default binding of
-`C-x`. The window that appears will let you browse the filesystem to
-find a file to attach. In this window, `o` opens the selected file with
-your URL open command to let you preview your choice, `Enter` enters the
-selected directory or selects the current file for attachment, and arrow
-keys change selection. Once you've attached a file, you'll see the text
-`(1 attachment)` above your message editor. You can attach additional
-files or remove existing attachments by pressing `C-x` again.
+* [Frequently asked questions](docs/FAQ.md)
+* [Matterhorn User Guide](docs/UserGuide.md)
+* Built-in help (`/help`)
+* [Command list](docs/commands.md)
+* [Keybinding list](docs/keybindings.md)
+* Chat with the developers on [the Mattermost Community server](https://community.mattermost.com/core/channels/matterhorn)
+* Get notified about new Matterhorn releases by following
+  [our Twitter account](https://twitter.com/matterhorn_chat)
 
 # Features
 
@@ -240,6 +62,7 @@
 * Rebindable keys (see `/help keybindings`)
 * Message editor with kill/yank buffer and readline-style keybindings
 * Support for adding and removing emoji post reactions
+* Support for channel muting
 * Tab-completion of:
   * Usernames: type `@`, then `Tab` to cycle through matches
   * Channel names: type `~`, then `Tab` to cycle through matches
@@ -262,45 +85,6 @@
   `activityNotifyCommand` configuration setting and
   `docs/notification-scripts.md` for details).
 
-# Spell Checking Support
-
-Matterhorn uses `aspell` to perform spell-checking of your message
-input. To use this feature:
-
- * Install `aspell` and ensure that your installation includes
-   dictionaries corresponding to your `LANG` setting. To check this, ask
-   `aspell` to check some input:
-   ```
-   $ echo stuff | aspell -a
-   Error: No word lists can be found for the language "en".
-   $ echo $LANG
-   en_US
-   ```
-   If Aspell succeeds, the output will look like this:
-   ```
-   @(#) International Ispell Version 3.1.20 (but really Aspell 0.60.6.1)
-   *
-   ```
- * Set `enableAspell` to `True` in your `config.ini`
- * Enter any message input in the message editor in `matterhorn`. After
-   a short delay after you stop typing, misspelled words will turn red.
-
-# Emoji
-
-Matterhorn loads its emoji list (for auto-completion of `:...:`) at
-startup. It looks for an `emoji.json` file in the following locations
-and in the following order:
-
-* `~/.config/matterhorn/emoji.json`. This option is to support emoji
-  list installation and customization.
-* `MHBIN/emoji/emoji.json`, where `MHBIN` is the directory containing
-  the `matterhorn` binary. This option is to make it convenient to use
-  emoji with `matterhorn` from releases.
-
-The `emoji.json` is included in the Matterhorn releases
-and is obtained from [the Mattermost web client source
-tree](https://github.com/mattermost/mattermost-webapp/blob/master/utils/emoji.json).
-
 # Our Versioning Scheme
 
 Matterhorn version strings will be of the form `ABBCC.X.Y` where ABBCC
@@ -348,7 +132,7 @@
 
  - If you are new to Haskell and are unsure how much Haskell you need
    to know in order to contribute, please see [our list of Haskell
-   skills needed](HASKELL.md).
+   skills needed](docs/HASKELL.md).
  - Please base all patches against the `develop` branch unless you are
    specifically fixing a bug in a released version, in which case
    `master` is a fine place to start. Please also do this for submodules
@@ -362,99 +146,14 @@
    the codebase.
  - We follow a few development practices to support our project and it
    helps when contributors are aware of these. Please see
-   `docs/PRACTICES.md` for more information.
+   [our practices document](docs/PRACTICES.md) for more information.
 
-## Building
+# Building
 
 If you just want to run Matterhorn, we strongly suggest running a binary
 release (see above). *Building from source is only recommended if you
 intend to contribute.*
 
 If you want to contribute changes to Matterhorn, you'll need to build
-it from source. To do that you'll need an appropriate `ghc`/`cabal`
-installation (see the latest Travis-CI builds for tested versions).
-You'll also need a GitHub account, since our Git submodules are set up
-to use SSH with GitHub. (But that should be fine since you'll need a
-GitHub account to contribute anyway.)
-
-`matterhorn` is built by running the following commands:
-
-```
-$ git pull
-$ git submodule update --init
-$ ./build.sh
-```
-
-# Frequently Asked Questions
-
-## Does matterhorn support Gitlab authentication?
-
-Matterhorn supports GitLab authentication indirectly. In order to use
-Matterhorn with GitLab authentication, see the Authentication section on
-Matterhorn details for use of session tokens.
-
-## Does matterhorn support Mattermost Personal Access Tokens?
-
-Yes. See the Authentication section above.
-
-## How can I get Matterhorn to render emphasized Markdown text with an italic font?
-
-In `~/.config/matterhorn/theme.ini`,
-```
-[other]
-markdownEmph.style = [italic]
-```
-and in `~/.config/matterhorn/config.ini`,
-```
-themeCustomizationFile: theme.ini
-```
-
-This is known to work on `gnome-terminal` version `3.32.2`, VTE version
-`0.56.3`; it may work for you, too. Many terminal emulators do not
-support italics at all or without various hacks. Let us know what works
-for you!
-
-## I enabled italicized text in my theme configuration. Why doesn't it work?
-
-Most terminfo files for typical terminal configurations do not provide
-support for italicized text. If your terminal emulator supports italics,
-you must enable it in your terminfo database in order to use it in
-Matterhorn. For more information, see these links:
-
-* http://www.nerdyweekly.com/posts/enable-italic-text-vim-tmux-gnome-terminal/
-* https://medium.com/@dubistkomisch/how-to-actually-get-italics-and-true-colour-to-work-in-iterm-tmux-vim-9ebe55ebc2be
-* https://github.com/tmux/tmux/blob/2.1/FAQ#L355-L383
-
-## I am seeing malformed characters or display corruption when I run matterhorn in my terminal. What could be causing this?
-
-Some terminal emulators cannot handle the extra escaping that occurs
-when the URL hyperlinking mode is enabled. Try setting `hyperlinkUrls =
-False` in your `config.ini` file.
-
-## Does Matterhorn support graphical emoji?
-
-At present Matterhorn does not reliably support graphical emoji due to
-the lack of consistent support for wide Unicode characters in various
-terminal emulators. Results may vary, and use of emoji characters may
-cause terminal rendering issues depending on the terminal emulator in
-use.
-
-## I'm running Matterhorn in Tmux. How can I paste tmux buffers into Matterhorn's editor?
-
-By default, `tmux`'s `paste-buffer` binding, `prefix-]`, pastes buffer
-text by replaying it as terminal input. This will cause unwanted
-behavior when Matterhorn receives that text and sends out each input
-line as a separate message. But `tmux` supports bracketed paste mode
-to make a `tmux` paste a block of text as *one* Matterhorn message.
-It can be enabled by changing the behavior of `prefix-]` in the Tmux
-configuration:
-
-```
-unbind-key -T prefix ]
-bind-key -T prefix ] paste-buffer -p
-```
-
-## I'm using Mattermost through an Nginx proxy and I keep getting disconnected.
-
-You might need to adjust your Nginx proxy settings.
-For context, see [this potentially related report](https://github.com/matterhorn-chat/matterhorn/issues/578).
+it from source. See [our building instructions](docs/BUILDING.md) for
+details.
diff --git a/docs/commands.md b/docs/commands.md
--- a/docs/commands.md
+++ b/docs/commands.md
@@ -16,7 +16,7 @@
 | `/hide` | Hide the current DM or group channel from the channel list |
 | `/join` | Find a channel to join |
 | `/join <~channel>` | Join the specified channel |
-| `/leave` | Leave the current channel |
+| `/leave` | Leave a normal channel or hide a DM channel |
 | `/left` | Focus on the previous channel |
 | `/log-mark <message>` | Add a custom marker message to the Matterhorn debug log |
 | `/log-snapshot <path>` | Dump the current debug log buffer to the specified path |
@@ -29,6 +29,7 @@
 | `/msg` | Search for a user to enter a private chat |
 | `/msg <@user>` | Chat with the specified user |
 | `/msg <@user> <message or command>` | Go to a user's channel and send the specified message or command |
+| `/notify-prefs` | Edit the current channel's notification preferences |
 | `/pinned-posts` | Open a window of this channel's pinned posts |
 | `/purpose <purpose>` | Set the current channel's purpose |
 | `/quit` | Exit Matterhorn |
@@ -44,3 +45,4 @@
 | `/toggle-channel-list` | Toggle channel list visibility |
 | `/topic <topic>` | Set the current channel's topic (header) |
 | `/user` | Show users to initiate a private DM chat channel |
+| `/username-attribute <@user>` | Display the attribute used to color the specified username |
diff --git a/docs/keybindings.md b/docs/keybindings.md
--- a/docs/keybindings.md
+++ b/docs/keybindings.md
@@ -23,7 +23,7 @@
 | `C-r` | `reply-recent` | Reply to the most recent message |
 | `M-p` | `toggle-message-preview` | Toggle message preview |
 | `F2` | `toggle-channel-list-visibility` | Toggle channel list visibility |
-| `M-k` | `invoke-editor` | Invoke *$EDITOR* to edit the current message |
+| `M-k` | `invoke-editor` | Invoke `$EDITOR` to edit the current message |
 | `C-g` | `enter-fast-select` | Enter fast channel selection mode |
 | `C-q` | `quit` | Quit |
 | `Tab` | (non-customizable key) | Tab-complete forward |
@@ -31,7 +31,7 @@
 | `Up` | `scroll-up` | Scroll up in the channel input history |
 | `Down` | `scroll-down` | Scroll down in the channel input history |
 | `PgUp` | `page-up` | Page up in the channel message list (enters message select mode) |
-| `Home` | `scroll-top` | Scroll to top of channel message list |
+| `S-Home` | `select-oldest-message` | Scroll to top of channel message list |
 | `C-n` | `focus-next-channel` | Change to the next channel in the channel list |
 | `C-p` | `focus-prev-channel` | Change to the previous channel in the channel list |
 | `M-a` | `focus-next-unread` | Change to the next channel with unread messages or return to the channel marked '~' |
@@ -114,6 +114,16 @@
 | `f` | `flag-message` | Toggle the selected message flag |
 | `Enter` | `activate-list-item` | Jump to and select current message |
 
+# Theme List Window
+| Keybinding | Event Name | Description |
+| ---------- | ---------- | ----------- |
+| `Esc`, `C-c` | `cancel` | Close the theme list |
+| `C-p`, `Up` | `search-select-up` | Select the previous theme |
+| `C-n`, `Down` | `search-select-down` | Select the next theme |
+| `PgDown` | `page-down` | Page down in the theme list |
+| `PgUp` | `page-up` | Page up in the theme list |
+| `Enter` | `activate-list-item` | Switch to the selected color theme |
+
 # User Listings
 | Keybinding | Event Name | Description |
 | ---------- | ---------- | ----------- |
@@ -156,6 +166,8 @@
 | ---------- | ---------- | ----------- |
 | `PgUp` | `page-up` | Page up |
 | `PgDown` | `page-down` | Page down |
+| `S-Left` | `page-left` | Page left |
+| `S-Right` | `page-right` | Page right |
 | `Up` | `scroll-up` | Scroll up |
 | `Down` | `scroll-down` | Scroll down |
 | `Left` | `scroll-left` | Scroll left |
@@ -182,4 +194,10 @@
 | `a` | `add-to-attachment-list` | Add a new attachment to the attachment list |
 | `o` | `open-attachment` | Open the selected attachment using the URL open command |
 | `d` | `delete-from-attachment-list` | Delete the selected attachment from the attachment list |
+
+# Attachment File Browser
+| Keybinding | Event Name | Description |
+| ---------- | ---------- | ----------- |
+| `Esc`, `C-c` | `cancel` | Cancel attachment file browse |
+| `o` | `open-attachment` | Open the selected file using the URL open command |
 
diff --git a/matterhorn.cabal b/matterhorn.cabal
--- a/matterhorn.cabal
+++ b/matterhorn.cabal
@@ -1,5 +1,5 @@
 name:                matterhorn
-version:             50200.9.0
+version:             50200.10.0
 synopsis:            Terminal client for the Mattermost chat system
 description:         This is a terminal client for the Mattermost chat
                      system. Please see the README for a list of
@@ -59,13 +59,14 @@
                        State.Logging
                        State.Messages
                        State.MessageSelect
+                       State.NotifyPrefs
                        State.PostListOverlay
+                       State.ThemeListOverlay
                        State.ReactionEmojiListOverlay
                        State.Reactions
                        State.Setup
                        State.Setup.Threads
                        State.Setup.Threads.Logging
-                       State.Themes
                        State.UrlSelect
                        State.ListOverlay
                        State.UserListOverlay
@@ -75,6 +76,7 @@
                        Themes
                        Draw
                        Emoji
+                       Draw.RichText
                        Draw.ManageAttachments
                        Draw.Autocomplete
                        Draw.Main
@@ -86,11 +88,13 @@
                        Draw.LeaveChannelConfirm
                        Draw.DeleteChannelConfirm
                        Draw.PostListOverlay
+                       Draw.ThemeListOverlay
                        Draw.UserListOverlay
                        Draw.ListOverlay
                        Draw.URLList
                        Draw.Util
                        Draw.TabbedWindow
+                       Draw.NotifyPrefs
                        InputHistory
                        IOUtil
                        Events
@@ -101,6 +105,7 @@
                        Events.Main
                        Events.ChannelSelect
                        Events.PostListOverlay
+                       Events.ThemeListOverlay
                        Events.UrlSelect
                        Events.UserListOverlay
                        Events.ChannelListOverlay
@@ -108,6 +113,7 @@
                        Events.LeaveChannelConfirm
                        Events.DeleteChannelConfirm
                        Events.TabbedWindow
+                       Events.EditNotifyPrefs
                        Windows.ViewMessage
                        HelpTopics
                        KeyMap
@@ -121,22 +127,25 @@
                        Types.DirectionalSeq
                        Types.KeyEvents
                        Types.Messages
+                       Types.RichText
                        Types.Users
-                       Types.UserNames
                        Types.Posts
                        FilePaths
                        TeamSelect
                        Login
-                       Markdown
                        Options
                        Util
                        Paths_matterhorn
   default-extensions:  OverloadedStrings,
                        ScopedTypeVariables,
                        NoImplicitPrelude
+
   ghc-options:         -Wall -threaded -with-rtsopts=-I0 -Wcompat
+  if impl(ghc >= 8.2)
+    ghc-options: -fhide-source-paths
+
   build-depends:       base                 >=4.8      && <5
-                     , mattermost-api       == 50200.6.0
+                     , mattermost-api       == 50200.7.0
                      , base-compat          >= 0.9     && < 0.12
                      , unordered-containers >= 0.2     && < 0.3
                      , containers           >= 0.5.7   && < 0.7
@@ -150,9 +159,9 @@
                      , config-ini           >= 0.2.2.0 && < 0.3
                      , process              >= 1.4     && < 1.7
                      , microlens-platform   >= 0.3     && < 0.5
-                     , brick                >= 0.52.1  && < 0.53
+                     , brick                >= 0.55    && < 0.56
                      , brick-skylighting    >= 0.2     && < 0.4
-                     , vty                  >= 5.28    && < 5.29
+                     , vty                  >= 5.30    && < 5.31
                      , word-wrap            >= 0.4.0   && < 0.5
                      , transformers         >= 0.4     && < 0.6
                      , text-zipper          >= 0.10    && < 0.11
@@ -190,18 +199,22 @@
                     , TimeUtils
                     , Types.Messages
                     , Types.Posts
-                    , Types.UserNames
                     , Types.Common
                     , Types.DirectionalSeq
+                    , Types.RichText
+                    , Constants
                     , Prelude.MH
   default-language:   Haskell2010
   default-extensions: OverloadedStrings
                     , ScopedTypeVariables
   ghc-options:        -Wall -fno-warn-orphans -Wcompat
+  if impl(ghc >= 8.2)
+    ghc-options: -fhide-source-paths
+
   hs-source-dirs:     src, test
   build-depends:      base                 >=4.7      && <5
                     , base-compat          >= 0.9     && < 0.12
-                    , brick                >= 0.52.1  && < 0.53
+                    , brick                >= 0.55    && < 0.56
                     , bytestring           >= 0.10    && < 0.11
                     , cheapskate           >= 0.1     && < 0.2
                     , checkers             >= 0.4     && < 0.6
@@ -212,8 +225,8 @@
                     , filepath             >= 1.4     && < 1.5
                     , hashable             >= 1.2     && < 1.4
                     , Hclip                >= 3.0     && < 3.1
-                    , mattermost-api       == 50200.6.0
-                    , mattermost-api-qc    == 50200.6.0
+                    , mattermost-api       == 50200.7.0
+                    , mattermost-api-qc    == 50200.7.0
                     , microlens-platform   >= 0.3     && < 0.5
                     , mtl                  >= 2.2     && < 2.3
                     , process              >= 1.4     && < 1.7
@@ -233,7 +246,7 @@
                     , Unique               >= 0.4     && < 0.5
                     , unordered-containers >= 0.2     && < 0.3
                     , vector               <  0.13
-                    , vty                  >= 5.28    && < 5.29
+                    , vty                  >= 5.30    && < 5.31
                     , xdg-basedir          >= 0.2     && < 0.3
                     , semigroups           >= 0.18    && < 0.20
                     , uuid                 >= 1.3     && < 1.4
diff --git a/src/App.hs b/src/App.hs
--- a/src/App.hs
+++ b/src/App.hs
@@ -38,6 +38,7 @@
       ReactionEmojiListOverlay      -> showFirstCursor s cs
       ChannelListOverlay            -> showFirstCursor s cs
       ManageAttachmentsBrowseFiles  -> showFirstCursor s cs
+      ThemeListOverlay              -> showFirstCursor s cs
       LeaveChannelConfirm           -> Nothing
       DeleteChannelConfirm          -> Nothing
       MessageSelect                 -> Nothing
@@ -47,6 +48,7 @@
       ViewMessage                   -> Nothing
       ShowHelp _ _                  -> Nothing
       UrlSelect                     -> Nothing
+      EditNotifyPrefs               -> Nothing
   , appHandleEvent  = Events.onEvent
   , appStartEvent   = return
   , appAttrMap      = (^.csResources.crTheme)
diff --git a/src/Command.hs b/src/Command.hs
--- a/src/Command.hs
+++ b/src/Command.hs
@@ -22,6 +22,7 @@
 import qualified Network.Mattermost.Types as MM
 
 import           Connection ( connectWebsockets )
+import           Constants ( userSigil, normalChannelSigil )
 import           HelpTopics
 import           Scripts
 import           State.Help
@@ -30,10 +31,13 @@
 import           State.ChannelSelect
 import           State.Logging
 import           State.PostListOverlay
-import           State.Themes
 import           State.UserListOverlay
 import           State.ChannelListOverlay
+import           State.ThemeListOverlay
+import           State.NotifyPrefs
+import           State.Common ( postInfoMessage )
 import           State.Users
+import           Themes ( attrForUsername )
 import           Types
 
 
@@ -120,7 +124,7 @@
     NoArg $ \ () ->
       enterChannelMembersUserList
 
-  , Cmd "leave" "Leave the current channel" NoArg $ \ () ->
+  , Cmd "leave" "Leave a normal channel or hide a DM channel" NoArg $ \ () ->
       startLeaveCurrentChannel
 
   , Cmd "join" "Find a channel to join" NoArg $ \ () ->
@@ -130,7 +134,7 @@
       joinChannelByName n
 
   , Cmd "theme" "List the available themes" NoArg $ \ () ->
-      listThemes
+      enterThemeListMode
 
   , Cmd "theme" "Set the color theme"
     (TokenArg "theme" NoArg) $ \ (themeName, ()) ->
@@ -156,6 +160,10 @@
     (UserArg NoArg) $ \ (name, ()) ->
         changeChannelByName name
 
+  , Cmd "username-attribute" "Display the attribute used to color the specified username"
+    (UserArg NoArg) $ \ (name, ()) ->
+        displayUsernameAttribute name
+
   , Cmd "msg" "Go to a user's channel and send the specified message or command"
     (UserArg $ LineArg "message or command") $ \ (name, msg) -> do
         withFetchedUserMaybe (UserFetchByUsername name) $ \foundUser -> do
@@ -248,7 +256,17 @@
   , Cmd "search" "Search for posts with given terms" (LineArg "terms") $
       enterSearchResultPostListMode
 
+  , Cmd "notify-prefs" "Edit the current channel's notification preferences" NoArg $ \_ ->
+          enterEditNotifyPrefsMode
+
   ]
+
+displayUsernameAttribute :: Text -> MH ()
+displayUsernameAttribute name = do
+    let an = attrForUsername trimmed
+        trimmed = trimUserSigil name
+    postInfoMessage $ "The attribute used for " <> userSigil <> trimmed <>
+                      " is " <> (attrNameToConfig an)
 
 execMMCommand :: Text -> Text -> MH ()
 execMMCommand name rest = do
diff --git a/src/Config.hs b/src/Config.hs
--- a/src/Config.hs
+++ b/src/Config.hs
@@ -111,6 +111,8 @@
       (configActivityBell defaultConfig)
     configHyperlinkingMode <- fieldFlagDef "hyperlinkURLs"
       (configHyperlinkingMode defaultConfig)
+    configMessageSelectAfterURLOpen <- fieldFlagDef "messageSelectAfterURLOpen"
+      (configMessageSelectAfterURLOpen defaultConfig)
     configPass <- (Just . PasswordCommand <$> field "passcmd") <!>
                   (Just . PasswordString  <$> field "pass") <!>
                   pure Nothing
@@ -241,6 +243,7 @@
            , configUserKeys                    = mempty
            , configShowTypingIndicator         = False
            , configHyperlinkingMode            = True
+           , configMessageSelectAfterURLOpen   = False
            , configSyntaxDirs                  = []
            , configDirectChannelExpirationDays = 7
            , configCpuUsagePolicy              = MultipleCPUs
diff --git a/src/Constants.hs b/src/Constants.hs
--- a/src/Constants.hs
+++ b/src/Constants.hs
@@ -3,6 +3,8 @@
   , userTypingExpiryInterval
   , numScrollbackPosts
   , previewMaxHeight
+  , normalChannelSigil
+  , userSigil
   )
 where
 
@@ -24,3 +26,10 @@
 -- | The maximum height of the message preview, in lines.
 previewMaxHeight :: Int
 previewMaxHeight = 5
+
+-- Sigils
+normalChannelSigil :: Text
+normalChannelSigil = "~"
+
+userSigil :: Text
+userSigil = "@"
diff --git a/src/Draw.hs b/src/Draw.hs
--- a/src/Draw.hs
+++ b/src/Draw.hs
@@ -12,6 +12,7 @@
 import Draw.DeleteChannelConfirm
 import Draw.LeaveChannelConfirm
 import Draw.Main
+import Draw.ThemeListOverlay
 import Draw.PostListOverlay
 import Draw.ShowHelp
 import Draw.UserListOverlay
@@ -19,6 +20,7 @@
 import Draw.ReactionEmojiListOverlay
 import Draw.TabbedWindow
 import Draw.ManageAttachments
+import Draw.NotifyPrefs
 import Types
 
 
@@ -33,6 +35,7 @@
         MessageSelect              -> drawMain True st
         MessageSelectDeleteConfirm -> drawMain True st
         DeleteChannelConfirm       -> drawDeleteChannelConfirm st
+        ThemeListOverlay           -> drawThemeListOverlay st
         PostListOverlay contents   -> drawPostListOverlay contents st
         UserListOverlay            -> drawUserListOverlay st
         ChannelListOverlay         -> drawChannelListOverlay st
@@ -40,3 +43,4 @@
         ViewMessage                -> drawTabbedWindow (st^.csViewedMessage.singular _Just._2) st : drawMain False st
         ManageAttachments          -> drawManageAttachments st
         ManageAttachmentsBrowseFiles -> drawManageAttachments st
+        EditNotifyPrefs            -> drawNotifyPrefs st : drawMain False st
diff --git a/src/Draw/Autocomplete.hs b/src/Draw/Autocomplete.hs
--- a/src/Draw/Autocomplete.hs
+++ b/src/Draw/Autocomplete.hs
@@ -15,6 +15,7 @@
 
 import           Network.Mattermost.Types ( User(..), Channel(..) )
 
+import           Constants ( normalChannelSigil )
 import           Draw.Util
 import           Themes
 import           Types
diff --git a/src/Draw/ChannelList.hs b/src/Draw/ChannelList.hs
--- a/src/Draw/ChannelList.hs
+++ b/src/Draw/ChannelList.hs
@@ -29,6 +29,7 @@
 
 import qualified Network.Mattermost.Types as MM
 
+import           Constants ( userSigil )
 import           Draw.Util
 import           State.Channels
 import           Themes
@@ -47,6 +48,7 @@
                          , entryIsRecent    :: Bool
                          , entryIsReturn    :: Bool
                          , entryIsCurrent   :: Bool
+                         , entryIsMuted     :: Bool
                          , entryUserStatus  :: Maybe UserStatus
                          }
 
@@ -82,12 +84,12 @@
                 (renderChannelListGroup st (\s e -> renderChannelListEntry myUsername_ $ mkChannelEntryData s e) <$>
                     Z.toList (st^.csFocus))
 
-renderChannelListGroupHeading :: ChannelListGroup -> Bool -> Widget Name
-renderChannelListGroupHeading g anyUnread =
-    let label = case g of
-            ChannelGroupPublicChannels -> "Public Channels"
-            ChannelGroupPrivateChannels -> "Private Channels"
-            ChannelGroupDirectMessages -> "Direct Messages"
+renderChannelListGroupHeading :: ChannelListGroup -> Widget Name
+renderChannelListGroupHeading g =
+    let (anyUnread, label) = case g of
+            ChannelGroupPublicChannels u -> (u, "Public Channels")
+            ChannelGroupPrivateChannels u -> (u, "Private Channels")
+            ChannelGroupDirectMessages u -> (u, "Direct Messages")
         addUnread = if anyUnread
                     then (<+> (withDefAttr unreadGroupMarkerAttr $ txt "*"))
                     else id
@@ -95,14 +97,12 @@
     in hBorderWithLabel labelWidget
 
 renderChannelListGroup :: ChatState
-                       -> (ChatState -> e -> (Bool, Widget Name))
+                       -> (ChatState -> e -> Widget Name)
                        -> (ChannelListGroup, [e])
                        -> Widget Name
 renderChannelListGroup st renderEntry (group, es) =
-    let heading = renderChannelListGroupHeading group anyUnread
-        entryResults = renderEntry st <$> es
-        (unreadFlags, entryWidgets) = unzip entryResults
-        anyUnread = or unreadFlags
+    let heading = renderChannelListGroupHeading group
+        entryWidgets = renderEntry st <$> es
     in if null entryWidgets
        then emptyWidget
        else vBox (heading : entryWidgets)
@@ -111,7 +111,7 @@
                    -> ChannelListEntry
                    -> ChannelListEntryData
 mkChannelEntryData st e =
-    ChannelListEntryData sigilWithSpace name unread mentions recent ret current status
+    ChannelListEntryData sigilWithSpace name unread mentions recent ret current muted status
     where
         cId = channelListEntryChannelId e
         Just chan = findChannelById cId (st^.csChannels)
@@ -119,6 +119,7 @@
         recent = isRecentChannel st cId
         ret = isReturnChannel st cId
         current = isCurrentChannel st cId
+        muted = isMuted chan
         (name, normalSigil, addSpace, status) = case e of
             CLChannel _ ->
                 (chan^.ccInfo.cdDisplayName, Nothing, False, Nothing)
@@ -144,14 +145,14 @@
 
 -- | Render an individual Channel List entry (in Normal mode) with
 -- appropriate visual decorations.
-renderChannelListEntry :: Text -> ChannelListEntryData -> (Bool, Widget Name)
-renderChannelListEntry myUName entry = (entryHasUnread entry, body)
+renderChannelListEntry :: Text -> ChannelListEntryData -> Widget Name
+renderChannelListEntry myUName entry = body
     where
     body = decorate $ decorateEntry entry $ decorateMentions $ padRight Max $
            entryWidget $ entrySigil entry <> entryLabel entry
     decorate = if | entryIsCurrent entry ->
                       visible . forceAttr currentChannelNameAttr
-                  | entryMentions entry > 0 ->
+                  | entryMentions entry > 0 && not (entryIsMuted entry) ->
                       forceAttr mentionsChannelAttr
                   | entryHasUnread entry ->
                       forceAttr unreadChannelAttr
@@ -165,25 +166,27 @@
         (<+> str "(9+)")
       | entryMentions entry > 0 =
         (<+> str ("(" <> show (entryMentions entry) <> ")"))
+      | entryIsMuted entry =
+        (<+> str "(m)")
       | otherwise = id
 
 -- | Render an individual entry when in Channel Select mode,
 -- highlighting the matching portion, or completely suppressing the
 -- entry if it doesn't match.
-renderChannelSelectListEntry :: Maybe ChannelSelectMatch -> ChatState -> ChannelSelectMatch -> (Bool, Widget Name)
+renderChannelSelectListEntry :: Maybe ChannelSelectMatch -> ChatState -> ChannelSelectMatch -> Widget Name
 renderChannelSelectListEntry curMatch st match =
     let ChannelSelectMatch preMatch inMatch postMatch _ entry = match
         maybeSelect = if (Just entry) == (matchEntry <$> curMatch)
                       then visible . withDefAttr currentChannelNameAttr
                       else id
         entryData = mkChannelEntryData st entry
-    in (False, maybeSelect $
-               decorateEntry entryData $
-               padRight Max $
-                 hBox [ txt $ entrySigil entryData <> preMatch
-                      , forceAttr channelSelectMatchAttr $ txt inMatch
-                      , txt postMatch
-                      ])
+    in maybeSelect $
+       decorateEntry entryData $
+       padRight Max $
+         hBox [ txt $ entrySigil entryData <> preMatch
+              , forceAttr channelSelectMatchAttr $ txt inMatch
+              , txt postMatch
+              ]
 
 -- If this channel is the return channel, add a decoration to denote
 -- that.
diff --git a/src/Draw/ChannelListOverlay.hs b/src/Draw/ChannelListOverlay.hs
--- a/src/Draw/ChannelListOverlay.hs
+++ b/src/Draw/ChannelListOverlay.hs
@@ -14,7 +14,7 @@
 import           Network.Mattermost.Lenses
 
 import           Draw.Main
-import           Draw.ListOverlay ( drawListOverlay )
+import           Draw.ListOverlay ( drawListOverlay, OverlayPosition(..) )
 import           Types
 import           Types.Common ( sanitizeUserText )
 import           Themes
@@ -25,6 +25,9 @@
     let overlay = drawListOverlay (st^.csChannelListOverlay) channelSearchScopeHeader
                                   channelSearchScopeNoResults channelSearchScopePrompt
                                   renderChannel
+                                  Nothing
+                                  OverlayCenter
+                                  80
     in joinBorders overlay : drawMain False st
 
 channelSearchScopePrompt :: ChannelSearchScope -> Widget Name
diff --git a/src/Draw/ListOverlay.hs b/src/Draw/ListOverlay.hs
--- a/src/Draw/ListOverlay.hs
+++ b/src/Draw/ListOverlay.hs
@@ -3,6 +3,7 @@
 
 module Draw.ListOverlay
   ( drawListOverlay
+  , OverlayPosition(..)
   )
 where
 
@@ -17,7 +18,8 @@
 import           Control.Monad.Trans.Reader ( withReaderT )
 import qualified Data.Foldable as F
 import qualified Data.Text as T
-import           Lens.Micro.Platform ( (%~) )
+import           Graphics.Vty ( imageWidth, translateX)
+import           Lens.Micro.Platform ( (%~), (.~), to )
 
 import           Themes
 import           Types
@@ -31,6 +33,11 @@
       withReaderT (& availWidthL  %~ (\ n -> n - (2 * pad))) $ render $ cropToContext contents
   }
 
+data OverlayPosition =
+    OverlayCenter
+    | OverlayUpperRight
+    deriving (Eq, Show)
+
 -- | Draw a ListOverlayState. This draws a bordered box with the
 -- overlay's search input and results list inside the box. The provided
 -- functions determine how to render the overlay in various states.
@@ -48,15 +55,33 @@
                 -> (Bool -> a -> Widget Name)
                 -- ^ The function to render an item from the overlay's
                 -- list
+                -> Maybe (Widget Name)
+                -- ^ The footer widget to render underneath the search
+                -- results
+                -> OverlayPosition
+                -- ^ How to position the overlay layer
+                -> Int
+                -- ^ The maximum window width in columns
                 -> Widget Name
-drawListOverlay st scopeHeader scopeNoResults scopePrompt renderItem =
-  centerLayer $ hLimitWithPadding 10 $ vLimit 25 $
-  borderWithLabel (withDefAttr clientEmphAttr $ scopeHeader scope) body
+drawListOverlay st scopeHeader scopeNoResults scopePrompt renderItem footer layerPos maxWinWidth =
+  positionLayer $ hLimitWithPadding 10 $ vLimit 25 $
+  hLimit maxWinWidth $
+  borderWithLabel title body
   where
+      title = withDefAttr clientEmphAttr $
+              hBox [ scopeHeader scope
+                   , case st^.listOverlayRecordCount of
+                         Nothing -> emptyWidget
+                         Just c -> txt " (" <+> str (show c) <+> txt ")"
+                   ]
+      positionLayer = case layerPos of
+          OverlayCenter -> centerLayer
+          OverlayUpperRight -> upperRightLayer
       body = vBox [ (padRight (Pad 1) promptMsg) <+>
                     renderEditor (txt . T.unlines) True (st^.listOverlaySearchInput)
                   , cursorPositionBorder
                   , showResults
+                  , fromMaybe emptyWidget footer
                   ]
       plural 1 = ""
       plural _ = "s"
@@ -66,7 +91,20 @@
           else case st^.listOverlaySearchResults.L.listSelectedL of
               Nothing -> hBorder
               Just _ ->
-                  let msg = "Found " <> show numSearchResults <> " result" <> plural numSearchResults
+                  let showingFirst = "Showing first " <> show numSearchResults <>
+                                     " result" <> plural numSearchResults
+                      showingAll = "Showing all " <> show numSearchResults <>
+                                   " result" <> plural numSearchResults
+                      showing = "Showing " <> show numSearchResults <>
+                                " result" <> plural numSearchResults
+                      msg = case getEditContents (st^.listOverlaySearchInput) of
+                          [""] ->
+                              case st^.listOverlayRecordCount of
+                                  Nothing -> showing
+                                  Just total -> if numSearchResults < total
+                                                then showingFirst
+                                                else showingAll
+                          _ -> showing
                   in hBorderWithLabel $ str $ "[" <> msg <> "]"
 
       scope = st^.listOverlaySearchScope
@@ -80,3 +118,17 @@
 
       renderedUserList = L.renderList renderItem True (st^.listOverlaySearchResults)
       numSearchResults = F.length $ st^.listOverlaySearchResults.L.listElementsL
+
+upperRightLayer :: Widget a -> Widget a
+upperRightLayer w =
+    Widget (hSize w) (vSize w) $ do
+        result <- render w
+        c <- getContext
+        let rWidth = result^.imageL.to imageWidth
+            leftPaddingAmount = max 0 $ c^.availWidthL - rWidth
+            paddedImage = translateX leftPaddingAmount $ result^.imageL
+            off = Location (leftPaddingAmount, 0)
+        if leftPaddingAmount == 0 then
+            return result else
+            return $ addResultOffset off
+                   $ result & imageL .~ paddedImage
diff --git a/src/Draw/Main.hs b/src/Draw/Main.hs
--- a/src/Draw/Main.hs
+++ b/src/Draw/Main.hs
@@ -33,13 +33,14 @@
 import           Draw.Autocomplete
 import           Draw.URLList
 import           Draw.Util
+import           Draw.RichText
 import           Events.Keybindings
 import           Events.MessageSelect
-import           Markdown
 import           State.MessageSelect
 import           Themes
 import           TimeUtils ( justAfter, justBefore )
 import           Types
+import           Types.RichText ( parseMarkdown )
 import           Types.KeyEvents
 
 
@@ -56,7 +57,7 @@
         msgTy = fromMaybe (if isEmoteCmd then CP Emote else CP NormalPost) overrideTy
     in if isCommand && not isEmoteCmd
        then Nothing
-       else Just $ Message { _mText          = getBlocks content
+       else Just $ Message { _mText          = parseMarkdown content
                            , _mMarkdownSource = content
                            , _mUser          = UserI False uId
                            , _mDate          = ServerTime $ UTCTime (fromGregorian 1970 1 1) 0
@@ -626,14 +627,16 @@
                      , txt " to manage)"
                      ]
 
-    showTypingUsers = case allTypingUsers (st^.csCurrentChannel.ccInfo.cdTypingUsers) of
-                        [] -> emptyWidget
-                        [uId] | Just un <- usernameForUserId uId st ->
-                           txt $ un <> " is typing"
-                        [uId1, uId2] | Just un1 <- usernameForUserId uId1 st
-                                     , Just un2 <- usernameForUserId uId2 st ->
-                           txt $ un1 <> " and " <> un2 <> " are typing"
-                        _ -> txt "several people are typing"
+    showTypingUsers =
+        let format = renderText' (myUsername st) hs
+        in case allTypingUsers (st^.csCurrentChannel.ccInfo.cdTypingUsers) of
+            [] -> emptyWidget
+            [uId] | Just un <- usernameForUserId uId st ->
+               format $ "[" <> userSigil <> un <> " is typing]"
+            [uId1, uId2] | Just un1 <- usernameForUserId uId1 st
+                         , Just un2 <- usernameForUserId uId2 st ->
+               format $ "[" <> userSigil <> un1 <> " and " <> userSigil <> un2 <> " are typing]"
+            _ -> format "[several people are typing]"
 
     showBusy = case st^.csWorkerIsBusy of
                  Just (Just n) -> hLimit 2 hBorder <+> txt (T.pack $ "*" <> show n)
diff --git a/src/Draw/Messages.hs b/src/Draw/Messages.hs
--- a/src/Draw/Messages.hs
+++ b/src/Draw/Messages.hs
@@ -18,7 +18,7 @@
 import           Prelude.MH
 
 import           Draw.Util
-import           Markdown
+import           Draw.RichText
 import           Themes
 import           Types
 import           Types.DirectionalSeq
diff --git a/src/Draw/NotifyPrefs.hs b/src/Draw/NotifyPrefs.hs
new file mode 100644
--- /dev/null
+++ b/src/Draw/NotifyPrefs.hs
@@ -0,0 +1,35 @@
+module Draw.NotifyPrefs
+  ( drawNotifyPrefs
+  )
+where
+
+import Prelude ()
+import Prelude.MH
+
+import Brick
+import Brick.Widgets.Border
+import Brick.Widgets.Center
+import Brick.Forms (renderForm)
+import Data.List (intersperse)
+
+import Draw.Util (renderKeybindingHelp)
+import Types
+import Types.KeyEvents
+import Themes
+
+drawNotifyPrefs :: ChatState -> Widget Name
+drawNotifyPrefs st =
+    let Just form = st^.csNotifyPrefs
+        label = forceAttr clientEmphAttr $ str "Notification Preferences"
+        formKeys = withDefAttr clientEmphAttr <$> txt <$> ["Tab", "BackTab"]
+        bindings = vBox $ hCenter <$> [ renderKeybindingHelp "Save" [FormSubmitEvent] <+> txt "  " <+>
+                                        renderKeybindingHelp "Cancel" [CancelEvent]
+                                      , hBox ((intersperse (txt "/") formKeys) <> [txt (":Cycle form fields")])
+                                      , hBox [withDefAttr clientEmphAttr $ txt "Space", txt ":Toggle form field"]
+                                      ]
+    in centerLayer $
+       vLimit 25 $
+       hLimit 39 $
+       joinBorders $
+       borderWithLabel label $
+       (padAll 1 $ renderForm form) <=> hBorder <=> bindings
diff --git a/src/Draw/PostListOverlay.hs b/src/Draw/PostListOverlay.hs
--- a/src/Draw/PostListOverlay.hs
+++ b/src/Draw/PostListOverlay.hs
@@ -16,6 +16,7 @@
 import           Network.Mattermost.Lenses
 import           Network.Mattermost.Types
 
+import           Constants ( userSigil )
 import           Draw.Main
 import           Draw.Messages
 import           Draw.Util
diff --git a/src/Draw/ReactionEmojiListOverlay.hs b/src/Draw/ReactionEmojiListOverlay.hs
--- a/src/Draw/ReactionEmojiListOverlay.hs
+++ b/src/Draw/ReactionEmojiListOverlay.hs
@@ -11,7 +11,7 @@
 import qualified Data.Text as T
 
 import           Draw.Main
-import           Draw.ListOverlay ( drawListOverlay )
+import           Draw.ListOverlay ( drawListOverlay, OverlayPosition(..) )
 import           Types
 import           Themes
 
@@ -23,6 +23,9 @@
                                   (const $ txt "No matching emoji found.")
                                   (const $ txt "Search emoji:")
                                   renderEmoji
+                                  Nothing
+                                  OverlayCenter
+                                  80
     in joinBorders overlay : drawMain False st
 
 renderEmoji :: Bool -> (Bool, T.Text) -> Widget Name
diff --git a/src/Draw/RichText.hs b/src/Draw/RichText.hs
new file mode 100644
--- /dev/null
+++ b/src/Draw/RichText.hs
@@ -0,0 +1,525 @@
+{-# LANGUAGE LambdaCase #-}
+{-# LANGUAGE MultiWayIf #-}
+{-# LANGUAGE ViewPatterns #-}
+{-# LANGUAGE ParallelListComp #-}
+{-# LANGUAGE RecordWildCards #-}
+module Draw.RichText
+  ( MessageData(..)
+  , renderRichText
+  , renderMessage
+  , renderText
+  , renderText'
+  , renderElementSeq
+  , cursorSentinel
+  , addEllipsis
+  , findVerbatimChunk
+  )
+where
+
+import           Prelude ()
+import           Prelude.MH
+
+import           Brick ( (<+>), Widget, hLimit, imageL
+                       , raw, render, Size(..), Widget(..)
+                       )
+import qualified Brick as B
+import qualified Brick.Widgets.Border as B
+import qualified Brick.Widgets.Skylighting as BS
+import qualified Data.Foldable as F
+import qualified Data.Map.Strict as Map
+import qualified Data.Sequence as Seq
+import           Data.Sequence ( ViewL(..)
+                               , ViewR(..)
+                               , (<|)
+                               , (|>)
+                               , viewl
+                               , viewr)
+import qualified Data.Sequence as S
+import qualified Data.Set as Set
+import qualified Data.Text as T
+import qualified Graphics.Vty as V
+import qualified Skylighting.Core as Sky
+
+import           Network.Mattermost.Lenses ( postEditAtL, postCreateAtL )
+import           Network.Mattermost.Types ( ServerTime(..) )
+
+import           Constants ( normalChannelSigil, userSigil )
+import           Themes
+import           Types ( Name, HighlightSet(..) )
+import           Types.Messages
+import           Types.Posts
+import           Types.RichText
+
+
+emptyHSet :: HighlightSet
+emptyHSet = HighlightSet Set.empty Set.empty mempty
+
+omittedUsernameType :: MessageType -> Bool
+omittedUsernameType = \case
+  CP Join -> True
+  CP Leave -> True
+  CP TopicChange -> True
+  _ -> False
+
+-- Add the edit sentinel to the end of the last block in the sequence.
+-- If the last block is a paragraph, append it to that paragraph.
+-- Otherwise, append a new block so it appears beneath the last
+-- block-level element.
+addEditSentinel :: ElementData -> Seq RichTextBlock -> Seq RichTextBlock
+addEditSentinel d bs =
+    case viewr bs of
+        EmptyR -> bs
+        (rest :> b) -> rest <> appendEditSentinel d b
+
+appendEditSentinel :: ElementData -> RichTextBlock -> Seq RichTextBlock
+appendEditSentinel sentinel b =
+    let s = Para (S.singleton m)
+        m = Element Normal sentinel
+    in case b of
+        Para is -> S.singleton $ Para (is |> Element Normal ESpace |> m)
+        _ -> S.fromList [b, s]
+
+-- | A bundled structure that includes all the information necessary
+-- to render a given message
+data MessageData =
+    MessageData { mdEditThreshold :: Maybe ServerTime
+                -- ^ If specified, any messages edited before this point
+                -- in time are not indicated as edited.
+                , mdShowOlderEdits :: Bool
+                -- ^ Indicates whether "edited" markers should be shown
+                -- for old messages (i.e., ignore the mdEditThreshold
+                -- value).
+                , mdShowReactions :: Bool
+                -- ^ Whether to render reactions.
+                , mdMessage :: Message
+                -- ^ The message to render.
+                , mdUserName :: Maybe Text
+                -- ^ The username of the message's author, if any. This
+                -- is passed here rather than obtaining from the message
+                -- because we need to do lookups in the ChatState to
+                -- compute this, and we don't pass the ChatState into
+                -- renderMessage.
+                , mdParentMessage :: Maybe Message
+                -- ^ The parent message of this message, if any.
+                , mdParentUserName :: Maybe Text
+                -- ^ The author of the parent message, if any.
+                , mdThreadState :: ThreadState
+                -- ^ The thread state of this message.
+                , mdRenderReplyParent :: Bool
+                -- ^ Whether to render the parent message.
+                , mdHighlightSet :: HighlightSet
+                -- ^ The highlight set to use to highlight usernames,
+                -- channel names, etc.
+                , mdIndentBlocks :: Bool
+                -- ^ Whether to indent the message underneath the
+                -- author's name (True) or just display it to the right
+                -- of the author's name (False).
+                , mdMessageWidthLimit :: Maybe Int
+                -- ^ A width override to use to wrap non-code blocks. If
+                -- unspecified, all blocks in the message will be
+                -- wrapped and truncated at the width specified by the
+                -- rendering context. If specified, all non-code blocks
+                -- will be wrapped at this width and code blocks will be
+                -- rendered using the context's width.
+                , mdMyUsername :: Text
+                -- ^ The username of the user running Matterhorn.
+                }
+
+-- | renderMessage performs markdown rendering of the specified message.
+renderMessage :: MessageData -> Widget Name
+renderMessage md@MessageData { mdMessage = msg, .. } =
+    let msgUsr = case mdUserName of
+          Just u -> if omittedUsernameType (msg^.mType) then Nothing else Just u
+          Nothing -> Nothing
+        botElem = if isBotMessage msg then B.txt "[BOT]" else B.emptyWidget
+        nameElems = case msgUsr of
+          Just un
+            | isEmote msg ->
+                [ B.withDefAttr pinnedMessageIndicatorAttr $ B.txt $ if msg^.mPinned then "[PIN]" else ""
+                , B.txt $ (if msg^.mFlagged then "[!] " else "") <> "*"
+                , colorUsername mdMyUsername un un
+                , botElem
+                , B.txt " "
+                ]
+            | otherwise ->
+                [ B.withDefAttr pinnedMessageIndicatorAttr $ B.txt $ if msg^.mPinned then "[PIN] " else ""
+                , colorUsername mdMyUsername un un
+                , botElem
+                , B.txt $ (if msg^.mFlagged then "[!]" else "") <> ": "
+                ]
+          Nothing -> []
+
+        -- Use the editing threshold to determine whether to append an
+        -- editing indication to this message.
+        maybeAugment bs = case msg^.mOriginalPost of
+            Nothing -> bs
+            Just p ->
+                if p^.postEditAtL > p^.postCreateAtL
+                then case mdEditThreshold of
+                    Just cutoff | p^.postEditAtL >= cutoff ->
+                        addEditSentinel (EEditSentinel True) bs
+                    _ -> if mdShowOlderEdits
+                         then addEditSentinel (EEditSentinel False) bs
+                         else bs
+                else bs
+
+        augmentedText = maybeAugment $ msg^.mText
+        msgWidget =
+            vBox $ (layout mdHighlightSet mdMessageWidthLimit nameElems augmentedText . viewl) augmentedText :
+                   catMaybes [msgAtch, msgReac]
+        replyIndent = B.Widget B.Fixed B.Fixed $ do
+            ctx <- B.getContext
+            -- NB: The amount subtracted here must be the total padding
+            -- added below (pad 1 + vBorder)
+            w <- B.render $ B.hLimit (ctx^.B.availWidthL - 2) msgWidget
+            B.render $ B.vLimit (V.imageHeight $ w^.B.imageL) $
+                B.padRight (B.Pad 1) B.vBorder B.<+> (B.Widget B.Fixed B.Fixed $ return w)
+        msgAtch = if Seq.null (msg^.mAttachments)
+          then Nothing
+          else Just $ B.withDefAttr clientMessageAttr $ vBox
+                 [ B.txt ("  [attached: `" <> a^.attachmentName <> "`]")
+                 | a <- toList (msg^.mAttachments)
+                 ]
+        msgReac = if Map.null (msg^.mReactions) || (not mdShowReactions)
+          then Nothing
+          else let renderR e us =
+                       let n = Set.size us
+                       in if | n == 1    -> " [" <> e <> "]"
+                             | n > 1     -> " [" <> e <> " " <> T.pack (show n) <> "]"
+                             | otherwise -> ""
+                   reactionMsg = Map.foldMapWithKey renderR (msg^.mReactions)
+               in Just $ B.withDefAttr emojiAttr $ B.txt ("   " <> reactionMsg)
+        withParent p =
+            case mdThreadState of
+                NoThread -> msgWidget
+                InThreadShowParent -> p B.<=> replyIndent
+                InThread -> replyIndent
+    in if not mdRenderReplyParent
+       then msgWidget
+       else case msg^.mInReplyToMsg of
+          NotAReply -> msgWidget
+          InReplyTo _ ->
+              case mdParentMessage of
+                  Nothing -> withParent (B.str "[loading...]")
+                  Just pm ->
+                      let parentMsg = renderMessage md
+                            { mdShowOlderEdits    = False
+                            , mdMessage           = pm
+                            , mdUserName          = mdParentUserName
+                            , mdParentMessage     = Nothing
+                            , mdRenderReplyParent = False
+                            , mdIndentBlocks      = False
+                            }
+                      in withParent (addEllipsis $ B.forceAttr replyParentAttr parentMsg)
+
+    where
+        layout :: HighlightSet -> Maybe Int -> [Widget Name] -> Seq RichTextBlock
+               -> ViewL RichTextBlock -> Widget Name
+        layout hs w nameElems bs xs | length xs > 1     = multiLnLayout hs w nameElems bs
+        layout hs w nameElems bs (Blockquote {} :< _) = multiLnLayout hs w nameElems bs
+        layout hs w nameElems bs (CodeBlock {} :< _)  = multiLnLayout hs w nameElems bs
+        layout hs w nameElems bs (HTMLBlock {} :< _)  = multiLnLayout hs w nameElems bs
+        layout hs w nameElems bs (List {} :< _)       = multiLnLayout hs w nameElems bs
+        layout hs w nameElems bs (Para inlns :< _)
+            | F.any breakCheck inlns                    = multiLnLayout hs w nameElems bs
+        layout hs w nameElems bs _                      = nameNextToMessage hs w nameElems bs
+
+        multiLnLayout hs w nameElems bs =
+            if mdIndentBlocks
+               then vBox [ hBox nameElems
+                         , hBox [B.txt "  ", renderRichText mdMyUsername hs ((subtract 2) <$> w) bs]
+                         ]
+               else nameNextToMessage hs w nameElems bs
+
+        nameNextToMessage hs w nameElems bs =
+            Widget Fixed Fixed $ do
+                nameResult <- render $ hBox nameElems
+                let newW = subtract (V.imageWidth (nameResult^.imageL)) <$> w
+                render $ hBox [raw (nameResult^.imageL), renderRichText mdMyUsername hs newW bs]
+
+        breakCheck e = eData e `elem` [ELineBreak, ESoftBreak]
+
+addEllipsis :: Widget a -> Widget a
+addEllipsis w = B.Widget (B.hSize w) (B.vSize w) $ do
+    ctx <- B.getContext
+    let aw = ctx^.B.availWidthL
+    result <- B.render w
+    let withEllipsis = (B.hLimit (aw - 3) $ B.vLimit 1 $ (B.Widget B.Fixed B.Fixed $ return result)) <+>
+                       B.str "..."
+    if (V.imageHeight (result^.B.imageL) > 1) || (V.imageWidth (result^.B.imageL) == aw) then
+        B.render withEllipsis else
+        return result
+
+-- Cursor sentinel for tracking the user's cursor position in previews.
+cursorSentinel :: Char
+cursorSentinel = '‸'
+
+-- Render markdown with username highlighting
+renderRichText :: Text -> HighlightSet -> Maybe Int -> Seq RichTextBlock -> Widget a
+renderRichText curUser hSet w =
+  B.vBox . toList . fmap (blockToWidget curUser hSet w) . addBlankLines
+
+-- Add blank lines only between adjacent elements of the same type, to
+-- save space
+addBlankLines :: Seq RichTextBlock -> Seq RichTextBlock
+addBlankLines = go' . viewl
+  where go' EmptyL = S.empty
+        go' (x :< xs) = go x (viewl xs)
+        go a@Para {} (b@Para {} :< rs) =
+             a <| blank <| go b (viewl rs)
+        go a@Header {} (b@Header {} :< rs) =
+             a <| blank <| go b (viewl rs)
+        go a@Blockquote {} (b@Blockquote {} :< rs) =
+             a <| blank <| go b (viewl rs)
+        go a@List {} (b@List {} :< rs) =
+             a <| blank <| go b (viewl rs)
+        go a@CodeBlock {} (b@CodeBlock {} :< rs) =
+             a <| blank <| go b (viewl rs)
+        go a@HTMLBlock {} (b@HTMLBlock {} :< rs) =
+             a <| blank <| go b (viewl rs)
+        go x (y :< rs) = x <| go y (viewl rs)
+        go x (EmptyL) = S.singleton x
+        blank = Para (S.singleton (Element Normal ESpace))
+
+-- Render text to markdown without username highlighting
+renderText :: Text -> Widget a
+renderText txt = renderText' "" emptyHSet txt
+
+renderText' :: Text -> HighlightSet -> Text -> Widget a
+renderText' curUser hSet t = renderRichText curUser hSet Nothing rtBs
+  where rtBs = parseMarkdown t
+
+vBox :: F.Foldable f => f (Widget a) -> Widget a
+vBox = B.vBox . toList
+
+hBox :: F.Foldable f => f (Widget a) -> Widget a
+hBox = B.hBox . toList
+
+header :: Int -> Widget a
+header n = B.txt (T.replicate n "#")
+
+maybeHLimit :: Maybe Int -> Widget a -> Widget a
+maybeHLimit Nothing w = w
+maybeHLimit (Just i) w = hLimit i w
+
+blockToWidget :: Text -> HighlightSet -> Maybe Int -> RichTextBlock -> Widget a
+blockToWidget curUser hSet w (Para is) =
+    toElementChunk curUser w is hSet
+blockToWidget curUser hSet w (Header n is) =
+    B.withDefAttr clientHeaderAttr $
+        hBox [B.padRight (B.Pad 1) $ header n, toElementChunk curUser (subtract 1 <$> w) is hSet]
+blockToWidget curUser hSet w (Blockquote is) =
+    maybeHLimit w $
+    addQuoting (vBox $ fmap (blockToWidget curUser hSet w) is)
+blockToWidget curUser hSet w (List _ l bs) =
+    maybeHLimit w $
+    blocksToList curUser l w bs hSet
+blockToWidget _ hSet _ (CodeBlock ci tx) =
+    let f = maybe rawCodeBlockToWidget (codeBlockToWidget (hSyntaxMap hSet)) mSyntax
+        mSyntax = do
+            lang <- codeBlockLanguage ci
+            Sky.lookupSyntax lang (hSyntaxMap hSet)
+    in f tx
+blockToWidget _ _ w (HTMLBlock t) =
+    maybeHLimit w $
+    textWithCursor t
+blockToWidget _ _ w (HRule) =
+    maybeHLimit w $
+    B.vLimit 1 (B.fill '*')
+
+quoteChar :: Char
+quoteChar = '>'
+
+addQuoting :: B.Widget n -> B.Widget n
+addQuoting w =
+    B.Widget B.Fixed (B.vSize w) $ do
+        ctx <- B.getContext
+        childResult <- B.render $ B.hLimit (ctx^.B.availWidthL - 2) w
+
+        let quoteBorder = B.raw $ V.charFill (ctx^.B.attrL) quoteChar 1 height
+            height = V.imageHeight $ childResult^.B.imageL
+
+        B.render $ B.hBox [ B.padRight (B.Pad 1) quoteBorder
+                          , B.Widget B.Fixed B.Fixed $ return childResult
+                          ]
+
+codeBlockToWidget :: Sky.SyntaxMap -> Sky.Syntax -> Text -> Widget a
+codeBlockToWidget syntaxMap syntax tx =
+    let result = Sky.tokenize cfg syntax tx
+        cfg = Sky.TokenizerConfig syntaxMap False
+    in case result of
+        Left _ -> rawCodeBlockToWidget tx
+        Right tokLines ->
+            let padding = B.padLeftRight 1 (B.vLimit (length tokLines) B.vBorder)
+            in (B.txt $ "[" <> Sky.sName syntax <> "]") B.<=>
+               (padding <+> BS.renderRawSource textWithCursor tokLines)
+
+rawCodeBlockToWidget :: Text -> Widget a
+rawCodeBlockToWidget tx =
+    B.withDefAttr codeAttr $
+        let padding = B.padLeftRight 1 (B.vLimit (length theLines) B.vBorder)
+            theLines = expandEmpty <$> T.lines tx
+            expandEmpty "" = " "
+            expandEmpty s  = s
+        in padding <+> (B.vBox $ textWithCursor <$> theLines)
+
+toElementChunk :: Text -> Maybe Int -> Seq Element -> HighlightSet -> Widget a
+toElementChunk curUser w es hSet = B.Widget B.Fixed B.Fixed $ do
+  ctx <- B.getContext
+  let width = fromMaybe (ctx^.B.availWidthL) w
+      ws    = fmap (renderElementSeq curUser) (wrapLine width hSet es)
+  B.render (vBox (fmap hBox ws))
+
+blocksToList :: Text -> ListType -> Maybe Int -> Seq (Seq RichTextBlock) -> HighlightSet -> Widget a
+blocksToList curUser lt w bs hSet = vBox
+  [ B.txt i <+> (vBox (fmap (blockToWidget curUser hSet w) b))
+  | b <- F.toList bs
+  | i <- is ]
+  where is = case lt of
+          Bullet _ -> repeat ("• ")
+          Numbered Period s ->
+            [ T.pack (show (n :: Int)) <> ". " | n <- [s..] ]
+          Numbered Paren s ->
+            [ T.pack (show (n :: Int)) <> ") " | n <- [s..] ]
+
+data SplitState = SplitState
+  { splitChunks  :: Seq (Seq Element)
+  , splitCurrCol :: Int
+  }
+
+wrapLine :: Int -> HighlightSet -> Seq Element -> Seq (Seq Element)
+wrapLine maxCols hSet = splitChunks . go (SplitState (S.singleton S.empty) 0)
+  where go st (viewl-> e :< es) = go st' es
+          where
+              HighlightSet { hUserSet = uSet, hChannelSet = cSet } = hSet
+
+              -- Right before we check the width of the token, we see
+              -- if the token is a user or channel reference. If so, we
+              -- check if it is valid. If it is valid, we leave it in
+              -- place; otherwise we translate it into an ordinary text
+              -- element so that it does not render highlighted as a
+              -- valid user or channel reference.
+              newElement = e { eData = newEData }
+              newEData = case eData e of
+                  EUser u ->
+                      if u `Set.member` uSet
+                      then EUser u
+                      else EText $ userSigil <> u
+                  EChannel c ->
+                      if c `Set.member` cSet
+                      then EChannel c
+                      else EText $ normalChannelSigil <> c
+                  d -> d
+
+              addHyperlink url el = setElementStyle (Hyperlink url (eStyle el)) el
+
+              st' =
+                  case newEData of
+                      EHyperlink url (Just labelEs) ->
+                          go st $ addHyperlink url <$> labelEs
+                      EImage url (Just labelEs) ->
+                          go st $ addHyperlink url <$> labelEs
+                      _ ->
+                          if | newEData == ESoftBreak || newEData == ELineBreak ->
+                                 st { splitChunks = splitChunks st |> S.empty
+                                    , splitCurrCol = 0
+                                    }
+                             | available >= eWidth ->
+                                 st { splitChunks  = addElement newElement (splitChunks st)
+                                    , splitCurrCol = splitCurrCol st + eWidth
+                                    }
+                             | newEData == ESpace ->
+                                 st { splitChunks = splitChunks st |> S.empty
+                                    , splitCurrCol = 0
+                                    }
+                             | otherwise ->
+                                 st { splitChunks  = splitChunks st |> S.singleton newElement
+                                    , splitCurrCol = eWidth
+                                    }
+              available = maxCols - splitCurrCol st
+              eWidth = elementWidth newElement
+              addElement x (viewr-> ls :> l) = ( ls |> (l |> x))
+              addElement _ _ = error "[unreachable]"
+        go st _                 = st
+
+renderElementSeq :: Text -> Seq Element -> Seq (Widget a)
+renderElementSeq curUser es = renderElement curUser <$> es
+
+renderElement :: Text -> Element -> Widget a
+renderElement curUser e = addStyle sty widget
+    where
+        sty = eStyle e
+        dat = eData e
+        addStyle s = case s of
+                Normal                  -> id
+                Emph                    -> B.withDefAttr clientEmphAttr
+                Strong                  -> B.withDefAttr clientStrongAttr
+                Code                    -> B.withDefAttr codeAttr
+                Hyperlink (URL url) innerSty ->
+                    B.hyperlink url . B.withDefAttr urlAttr .  addStyle innerSty
+        rawText = B.txt . removeCursor
+        widget = case dat of
+            -- Cursor sentinels get parsed as individual text nodes by
+            -- Cheapskate, meaning that we get a text node with exactly
+            -- one character in it. That's why we compare accordingly
+            -- above. In addition, since that character has no width, we
+            -- have to replace it with something that has a size (such
+            -- as a space) to get Brick's visibility logic to scroll the
+            -- viewport to get it into view.
+            EText t                      -> if t == T.singleton (cursorSentinel)
+                                            then B.visible $ B.txt " "
+                                            else rawText t
+
+            ESpace                       -> B.txt " "
+            ERawHtml t                   -> rawText t
+            EEditSentinel recent         -> let attr = if recent
+                                                       then editedRecentlyMarkingAttr
+                                                       else editedMarkingAttr
+                                            in B.withDefAttr attr $ B.txt editMarking
+            EUser u                      -> colorUsername curUser u $ userSigil <> u
+            EChannel c                   -> B.withDefAttr channelNameAttr $
+                                            B.txt $ normalChannelSigil <> c
+            EHyperlink (URL url) Nothing -> rawText url
+            EImage (URL url) Nothing     -> rawText url
+            EEmoji em                    -> B.withDefAttr emojiAttr $
+                                            B.txt $ ":" <> em <> ":"
+
+            -- Hyperlink and image nodes with labels should not appear
+            -- at this point because line-wrapping should break them up
+            -- into normal text node sequences with hyperlink styles
+            -- attached.
+            EHyperlink {}                -> rawText "(Report renderElement bug #1)"
+            EImage {}                    -> rawText "(Report renderElement bug #2)"
+
+            -- Line breaks should never need to get rendered since the
+            -- line-wrapping algorithm removes them.
+            ESoftBreak                   -> B.emptyWidget
+            ELineBreak                   -> B.emptyWidget
+
+textWithCursor :: Text -> Widget a
+textWithCursor t
+    | T.any (== cursorSentinel) t = B.visible $ B.txt $ removeCursor t
+    | otherwise = B.txt t
+
+removeCursor :: Text -> Text
+removeCursor = T.filter (/= cursorSentinel)
+
+editMarking :: Text
+editMarking = "(edited)"
+
+elementWidth :: Element -> Int
+elementWidth e =
+    case eData e of
+        EText t                      -> B.textWidth t
+        ERawHtml t                   -> B.textWidth t
+        EUser t                      -> T.length userSigil + B.textWidth t
+        EChannel t                   -> T.length normalChannelSigil + B.textWidth t
+        EEditSentinel _              -> B.textWidth editMarking
+        EImage (URL url) Nothing     -> B.textWidth url
+        EImage _ (Just is)           -> sum $ elementWidth <$> is
+        EHyperlink (URL url) Nothing -> B.textWidth url
+        EHyperlink _ (Just is)       -> sum $ elementWidth <$> is
+        EEmoji t                     -> B.textWidth t + 2
+        ESpace                       -> 1
+        ELineBreak                   -> 0
+        ESoftBreak                   -> 0
diff --git a/src/Draw/ShowHelp.hs b/src/Draw/ShowHelp.hs
--- a/src/Draw/ShowHelp.hs
+++ b/src/Draw/ShowHelp.hs
@@ -28,6 +28,7 @@
 import           Events.Keybindings
 import           Events.Main
 import           Events.MessageSelect
+import           Events.ThemeListOverlay
 import           Events.PostListOverlay
 import           Events.ShowHelp
 import           Events.UrlSelect
@@ -38,7 +39,7 @@
 import           Events.TabbedWindow
 import           Windows.ViewMessage
 import           HelpTopics ( helpTopics )
-import           Markdown ( renderText )
+import           Draw.RichText ( renderText )
 import           Options ( mhVersion )
 import           State.Editing ( editingKeyHandlers )
 import           Themes
@@ -53,6 +54,9 @@
 
 helpTopicDraw :: HelpTopic -> ChatState -> Widget Name
 helpTopicDraw topic st =
+    overrideAttr codeAttr helpEmphAttr $
+    hCenter $
+    hLimit helpContentWidth $
     case helpTopicScreen topic of
         MainHelp -> mainHelp (configUserKeys (st^.csResources.crConfiguration))
         ScriptHelp -> scriptHelp
@@ -61,23 +65,23 @@
         KeybindingHelp -> keybindingHelp (configUserKeys (st^.csResources.crConfiguration))
 
 mainHelp :: KeyConfig -> Widget Name
-mainHelp kc = commandHelp
+mainHelp kc = summary
   where
-    commandHelp = vBox $ [ padTop (Pad 1) $ hCenter $ withDefAttr helpEmphAttr $ str mhVersion
-                         , hCenter $ withDefAttr helpEmphAttr $ str mmApiVersion
-                         , padTop (Pad 1) $ hCenter $ withDefAttr helpEmphAttr $ txt "Help Topics"
-                         , drawHelpTopics
-                         , padTop (Pad 1) $ hCenter $ withDefAttr helpEmphAttr $ txt "Commands"
-                         , mkCommandHelpText
-                         , padTop (Pad 1) $ hCenter $ withDefAttr helpEmphAttr $ txt "Keybindings"
-                         ] <>
-                         (mkKeybindingHelp kc <$> keybindSections)
+    summary = vBox entries
+    entries = [ heading $ T.pack mhVersion
+              , headingNoPad $ T.pack mmApiVersion
+              , heading "Help Topics"
+              , drawHelpTopics
+              , heading "Commands"
+              , padTop (Pad 1) mkCommandHelpText
+              , heading "Keybindings"
+              ] <>
+              (mkKeybindingHelp kc <$> keybindSections)
 
     mkCommandHelpText :: Widget Name
     mkCommandHelpText =
-      let commandNameWidth = 4 + (maximum $ T.length <$> fst <$> commandHelpInfo)
-      in hCenter $
-         vBox [ (withDefAttr helpEmphAttr $ txt $ padTo commandNameWidth info) <+> renderText desc
+      let commandNameWidth = 2 + (maximum $ T.length <$> fst <$> commandHelpInfo)
+      in vBox [ (emph $ txt $ padTo commandNameWidth info) <+> renderText desc
               | (info, desc) <- commandHelpInfo
               ]
 
@@ -116,23 +120,23 @@
 drawHelpTopics =
     let allHelpTopics = drawTopic <$> helpTopics
         topicNameWidth = 4 + (maximum $ T.length <$> helpTopicName <$> helpTopics)
-        drawTopic t = (withDefAttr helpEmphAttr $ txt (padTo topicNameWidth $ helpTopicName t)) <+>
+        drawTopic t = (emph $ txt (padTo topicNameWidth $ helpTopicName t)) <+>
                       txt (helpTopicDescription t)
-    in (padBottom (Pad 1) $
-        hCenter $ renderText "Learn more about these topics with `/help <topic>`:") <=>
-       (hCenter $ vBox allHelpTopics)
+    in vBox $ (padBottom (Pad 1) $
+               para "Learn more about these topics with `/help <topic>`:")
+            : allHelpTopics
 
+helpContentWidth :: Int
+helpContentWidth = 72
+
 scriptHelp :: Widget Name
-scriptHelp = vBox
-  [ padTop (Pad 1) $ hCenter $ withDefAttr helpEmphAttr $ txt "Using Scripts"
-  , padTop (Pad 1) $ hCenter $ hLimit 100 $ vBox scriptHelpText
-  ]
-  where scriptHelpText = map (padTop (Pad 1) . renderText . mconcat)
+scriptHelp = heading "Using Scripts" <=> vBox scriptHelpText
+  where scriptHelpText = map paraL
           [ [ "Matterhorn has a special feature that allows you to use "
              , "prewritten shell scripts to preprocess messages. "
              , "For example, this can allow you to run various filters over "
              , "your written text, do certain kinds of automated formatting, "
-             , "or just automatically cowsay-ify a message.\n" ]
+             , "or just automatically cowsay-ify a message." ]
            , [ "These scripts can be any kind of executable file, "
              , "as long as the file lives in "
              , "*~/.config/matterhorn/scripts* (unless you've explicitly "
@@ -144,24 +148,24 @@
              , "that appeared on *stderr* is discarded; if it instead exits with "
              , "a failing exit code, your message is *not* sent, and you are "
              , "presented with whatever was printed on stderr as a "
-             , "local error message.\n" ]
-           , [ "To run a script, simply type\n" ]
-           , [ "> *> /sh [script-name] [my-message]*\n" ]
+             , "local error message." ]
+           , [ "To run a script, simply type" ]
+           , [ "> *> /sh [script-name] [my-message]*" ]
            , [ "And the script named *[script-name]* will be invoked with "
              , "the text of *[my-message]*. If the script does not exist, "
              , "or if it exists but is not marked as executable, you'll be "
-             , "presented with an appropriate error message.\n" ]
+             , "presented with an appropriate error message." ]
            , [ "For example, if you want to use a basic script to "
              , "automatically ROT13 your message, you can write a shell "
-             , "script using the standard Unix *tr* utility, like this:\n" ]
-           , [ "> *#!/bin/bash -e*\n"
-             , "> *tr '[A-Za-z]' '[N-ZA-Mn-za-m]'*\n\n" ]
+             , "script using the standard Unix *tr* utility, like this:" ]
+           , [ "> *#!/bin/bash -e*"
+             , "> *tr '[A-Za-z]' '[N-ZA-Mn-za-m]'*" ]
            , [ "Move this script to *~/.config/matterhorn/scripts/rot13* "
-             , "and be sure it's executable with\n" ]
-           , [ "> *$ chmod u+x ~/.config/matterhorn/scripts/rot13*\n\n" ]
+             , "and be sure it's executable with" ]
+           , [ "> *$ chmod u+x ~/.config/matterhorn/scripts/rot13*" ]
            , [ "after which you can send ROT13 messages with the "
              , "Matterhorn command " ]
-           , [ "> *> /sh rot13 Hello, world!*\n" ]
+           , [ "> *> /sh rot13 Hello, world!*" ]
            ]
 
 keybindingMarkdownTable :: KeyConfig -> Text
@@ -186,26 +190,25 @@
               "\n" <> (T.replicate (T.length n) "=")
 
 keybindingHelp :: KeyConfig -> Widget Name
-keybindingHelp kc = hCenter $ hLimit 100 $ vBox $
-  [ padTop (Pad 1) $ hCenter $ withDefAttr helpEmphAttr $ txt "Configurable Keybindings"
-  , padTop (Pad 1) $ hCenter $ vBox keybindingHelpText
+keybindingHelp kc = vBox $
+  [ heading "Configurable Keybindings"
+  , padBottom (Pad 1) $ vBox keybindingHelpText
   ] ++ keybindSectionWidgets
     ++
-  [ padTop (Pad 1) $ hCenter $ withDefAttr helpEmphAttr $ txt "Keybinding Syntax"
-  , padTop (Pad 1) $ hCenter $ vBox validKeys
+  [ headingNoPad "Keybinding Syntax"
+  , vBox validKeys
   ]
   where keybindSectionWidgets = sectionWidget <$> keybindSections
-        sectionWidget = mkKeybindEventSectionHelp kc keybindEventHelpWidget vBox mkSectionHeading
-        mkSectionHeading = hCenter . padTop (Pad 1) . withDefAttr helpEmphAttr . txt
+        sectionWidget = mkKeybindEventSectionHelp kc keybindEventHelpWidget vBox headingNoPad
 
-        keybindingHelpText = map (padTop (Pad 1) . renderText . mconcat)
+        keybindingHelpText = map paraL
           [ [ "Many of the keybindings used in Matterhorn can be "
             , "modified from within Matterhorn's **config.ini** file. "
             , "To do this, include a section called **[KEYBINDINGS]** "
             , "in your config file and use the event names listed below as "
             , "keys and the desired key sequence as values. "
             , "See the end of this page for documentation on the valid "
-            , "syntax for key sequences.\n"
+            , "syntax for key sequences."
             ]
           , [ "For example, by default, the keybinding to move to the next "
             , "channel in the public channel list is **"
@@ -215,34 +218,34 @@
             , prevChanBinding
             , "**. You might want to remap these "
             , "to other keys: say, **C-j** and **C-k**. We can do this with the following "
-            , "configuration snippet:\n"
+            , "configuration snippet:"
             ]
           , [ "```ini\n"
             , "[KEYBINDINGS]\n"
             , "focus-next-channel = C-j\n"
             , "focus-prev-channel = C-k\n"
-            , "```\n"
+            , "```"
             ]
           , [ "You can remap a command to more than one key sequence, in which "
             , "case any one of the key sequences provided can be used to invoke "
             , "the relevant command. To do this, provide the desired bindings as "
             , "a comma-separated list. Additionally, some key combinations are "
             , "used in multiple modes (such as URL select or help viewing) and "
-            , "therefore share the same name, such as **cancel** or **scroll-up**.\n"
+            , "therefore share the same name, such as **cancel** or **scroll-up**."
             ]
           , [ "Additionally, some keys simply cannot be remapped, mostly in the "
             , "case of editing keybindings. If you feel that a particular key "
             , "event should be rebindable and isn't, then please feel free to "
-            , "let us know by posting an issue in the Matterhorn issue tracker.\n"
+            , "let us know by posting an issue in the Matterhorn issue tracker."
             ]
           , [ "It is also possible to entirely unbind a key event by setting its "
             , "key to **unbound**, thus avoiding conflicts between default bindings "
-            , "and new ones:\n"
+            , "and new ones:"
             ]
           , [ "```ini\n"
             , "[KEYBINDINGS]\n"
             , "focus-next-channel = unbound\n"
-            , "```\n"
+            , "```"
             ]
           , [ "The rebindable key events, along with their **current** "
             , "values, are as follows:"
@@ -250,7 +253,7 @@
            ]
         nextChanBinding = ppBinding (getFirstDefaultBinding NextChannelEvent)
         prevChanBinding = ppBinding (getFirstDefaultBinding PrevChannelEvent)
-        validKeys = map (padTop (Pad 1) . renderText . mconcat)
+        validKeys = map paraL
           [ [ "The syntax used for key sequences consists of zero or more "
             , "single-character modifier characters followed by a keystroke, "
             , "all separated by dashes. The available modifier keys are "
@@ -282,12 +285,25 @@
             ]
           ]
 
+emph :: Widget a -> Widget a
+emph = withDefAttr helpEmphAttr
+
 para :: Text -> Widget a
-para t = padTop (Pad 1) $ hCenter (hLimit 72 $ padRight Max $ renderText t)
+para t = padTop (Pad 1) $ renderText t
 
+paraL :: [Text] -> Widget a
+paraL = para . mconcat
+
+heading :: Text -> Widget a
+heading = padTop (Pad 1) . headingNoPad
+
+headingNoPad :: Text -> Widget a
+headingNoPad t = hCenter $ emph $ renderText t
+
 syntaxHighlightHelp :: [FilePath] -> Widget a
-syntaxHighlightHelp dirs = overrideAttr codeAttr helpEmphAttr $ vBox
-  [ padTop (Pad 1) $ hCenter $ withDefAttr helpEmphAttr $ txt "Syntax Highlighting"
+syntaxHighlightHelp dirs = vBox
+  [ heading "Syntax Highlighting"
+
   , para $ "Matterhorn supports syntax highlighting in Markdown code blocks when the " <>
            "name of the code block language follows the block opening sytnax:"
   , para $ "```<language>"
@@ -307,26 +323,30 @@
   ]
 
 themeHelp :: Widget a
-themeHelp = overrideAttr codeAttr helpEmphAttr $ vBox
-  [ padTop (Pad 1) $ hCenter $ withDefAttr helpEmphAttr $ txt "Using Themes"
-  , padTop (Pad 1) $ hCenter $ renderText "Matterhorn provides these built-in color themes:"
-  , padTop (Pad 1) $ vBox $ hCenter <$> withDefAttr helpEmphAttr <$>
+themeHelp = vBox
+  [ heading "Using Themes"
+  , para "Matterhorn provides these built-in color themes:"
+  , padTop (Pad 1) $ vBox $ hCenter <$> emph <$>
                             txt <$> internalThemeName <$> internalThemes
-  , padTop (Pad 1) $ hCenter $ hLimit 72 $ renderText $
+  , para $
         "These themes can be selected with the */theme* command. To automatically " <>
         "select a theme at startup, set the *theme* configuration file option to one " <>
         "of the themes listed above."
-  , padTop (Pad 1) $ hCenter $ withDefAttr helpEmphAttr $ txt "Customizing the Theme"
-  , padTop (Pad 1) $ hCenter $ hLimit 72 $ renderText $
+
+  , heading "Customizing the Theme"
+  , para $
         "Theme customization is also supported. To customize the selected theme, " <>
         "create a theme customization file and set the `themeCustomizationFile` " <>
         "configuration option to the path to the customization file. If the path " <>
         "to the file is relative, Matterhorn will look for it in the same directory " <>
-        "as the Matterhorn configuration file.\n" <>
-        "  \n" <>
+        "as the Matterhorn configuration file."
+
+  , para $
         "Theme customization files are INI-style files that can customize any " <>
         "foreground color, background color, or style of any aspect of the " <>
-        "Matterhorn user interface. Here is an example:\n" <>
+        "Matterhorn user interface. Here is an example:"
+
+  , para $
         "```\n" <>
         "[default]\n" <>
         "default.fg = blue\n" <>
@@ -338,13 +358,17 @@
         attrNameToConfig clientEmphAttr <> ".fg = cyan\n" <>
         attrNameToConfig clientEmphAttr <> ".style = [bold, underline]\n" <>
         attrNameToConfig listSelectedFocusedAttr <> ".fg = brightGreen\n" <>
-        "```\n" <>
+        "```"
+
+  , para $
         "In the example above, the theme's default foreground and background colors " <>
         "are both customized to *blue* and *black*, respectively. The *default* section " <>
         "contains only customizations for the *default* attribute. All other customizations " <>
         "go in the *other* section. We can also set the style for attributes; we can either " <>
         "set just one style (as with the bold setting above) or multiple styles at once " <>
-        "(as in the bold/underline example).\n\n" <>
+        "(as in the bold/underline example).\n"
+
+  , para $
         "Available colors are:\n" <>
         " * black\n" <>
         " * red\n" <>
@@ -361,8 +385,9 @@
         " * brightBlue\n" <>
         " * brightMagenta\n" <>
         " * brightCyan\n" <>
-        " * brightWhite\n" <>
-        "  \n" <>
+        " * brightWhite"
+
+  , para $
         "Available styles are:\n" <>
         " * standout\n" <>
         " * underline\n" <>
@@ -370,39 +395,49 @@
         " * reverseVideo\n" <>
         " * blink\n" <>
         " * dim\n" <>
-        " * bold\n" <>
-        "  \n" <>
+        " * bold\n"
+
+  , para $
+        "It is also possible to specify RGB values using HTML syntax: `#RRGGBB`. " <>
+        "Bear in mind that such colors are clamped to the nearest 256-color palette " <>
+        "entry, so it is not possible to get the exact color specified.\n\n" <>
         "In addition, a special value of *default* is possible for either color " <>
         "setting of an attribute. This value indicates that the attribute should " <>
         "use the terminal emulator's default foreground or background color of " <>
         "choice rather than a specific ANSI color."
-  , padTop (Pad 1) $ hCenter $ withDefAttr helpEmphAttr $ txt "Username Highlighting"
-  , padTop (Pad 1) $ hCenter $ hLimit 72 $ renderText $
+
+  , heading "Username Highlighting"
+  , para $
         "Username colors are chosen by hashing each username and then using the hash " <>
         "to choose a color from a list of predefined username colors. If you would like " <>
         "to change the color in a given entry of this list, we provide the " <>
         "\"username.N\" attributes, where N is the index in the username color list."
-  , padTop (Pad 1) $ hCenter $ withDefAttr helpEmphAttr $ txt "Theme Attributes"
-  , padTop (Pad 1) $ hCenter $ hLimit 72 $ renderText $
+
+  , heading "Theme Attributes"
+  , para $
         "This section lists all possible theme attributes for use in customization " <>
         "files along with a description of how each one is used in Matterhorn. Each " <>
         "option listed can be set in the *other* section of the customization file. " <>
-        "Each provides three customization settings:\n" <>
+        "Each provides three customization settings:"
+
+  , para $
         " * *<option>.fg = <color>*\n" <>
         " * *<option>.bg = <color>*\n" <>
         " * *<option>.style = <style>* or *<option>.style = [<style>, ...]*\n"
 
-  , padTop (Pad 1) $ hCenter $ hLimit 72 $ renderText $
-        let names = sort $
-                    (\(n, msg) -> (attrNameToConfig n, msg)) <$>
-                    (M.toList $ themeDescriptions themeDocs)
-            mkEntry (opt, msg) = "*" <> opt <> "*\n" <> msg <> "\n"
-        in T.concat $ mkEntry <$> names
+  , let names = sort $
+                 (\(n, msg) -> (n, attrNameToConfig n, msg)) <$>
+                 (M.toList $ themeDescriptions themeDocs)
+        mkEntry (n, opt, msg) =
+            padTop (Pad 1) $
+            vBox [ hBox [ withDefAttr clientEmphAttr $ txt opt
+                        , padLeft Max $ forceAttr n $ txt "(demo)"
+                        ]
+                 , txt msg
+                 ]
+    in vBox $ mkEntry <$> names
   ]
 
-attrNameToConfig :: AttrName -> Text
-attrNameToConfig = T.pack . intercalate "." . attrNameComponents
-
 keybindSections :: [(Text, [KeyEventHandler])]
 keybindSections =
     [ ("Global Keybindings", globalKeyHandlers)
@@ -413,6 +448,7 @@
     , ("Message Select Mode", messageSelectKeyHandlers)
     , ("Text Editing", editingKeyHandlers (csEditState.cedEditor))
     , ("Flagged Messages", postListOverlayKeyHandlers)
+    , ("Theme List Window", themeListOverlayKeyHandlers)
     , ("User Listings", userListOverlayKeyHandlers)
     , ("Channel Search Window", channelListOverlayKeyHandlers)
     , ("Reaction Emoji Search Window", reactionEmojiListOverlayKeyHandlers)
@@ -420,12 +456,13 @@
     , ("Message Viewer: Message tab", viewMessageKeyHandlers)
     , ("Message Viewer: Reactions tab", viewMessageReactionsKeyHandlers)
     , ("Attachment List", attachmentListKeyHandlers)
+    , ("Attachment File Browser", attachmentBrowseKeyHandlers)
     ]
 
 helpBox :: Name -> Widget Name -> Widget Name
 helpBox n helpText =
     withDefAttr helpAttr $
-    borderWithLabel (withDefAttr helpEmphAttr $ txt "Matterhorn Help") $
+    borderWithLabel (emph $ txt "Matterhorn Help") $
     viewport HelpViewport Vertical $
     cached n helpText
 
@@ -437,8 +474,8 @@
 
 mkKeybindingHelp :: KeyConfig -> (Text, [KeyEventHandler]) -> Widget Name
 mkKeybindingHelp kc (sectionName, kbs) =
-    (hCenter $ padTop (Pad 1) $ withDefAttr helpEmphAttr $ txt sectionName) <=>
-    (hCenter $ vBox $ snd <$> sortWith fst results)
+    (heading sectionName) <=>
+    (padTop (Pad 1) $ hCenter $ vBox $ snd <$> sortWith fst results)
     where
         results = mkKeybindHelp kc <$> kbs
 
@@ -459,7 +496,7 @@
                                               | otherwise -> unbound
                 in T.intercalate ", " bindings
 
-        rendering = (withDefAttr helpEmphAttr $ txt $ padTo kbColumnWidth $
+        rendering = (emph $ txt $ padTo kbColumnWidth $
                       label) <+> txt " " <+>
                     (hLimit kbDescColumnWidth $ padRight Max $ renderText $
                      ehDescription $ kehHandler h)
@@ -480,10 +517,10 @@
     let evText = T.intercalate ", " evs
         label = case evName of
             Left s -> txt $ "; " <> s
-            Right s -> withDefAttr helpEmphAttr $ txt s
-    in vBox [ txt (padTo 72 ("; " <> desc))
+            Right s -> emph $ txt s
+    in padBottom (Pad 1) $
+       vBox [ txtWrap ("; " <> desc)
             , label <+> txt (" = " <> evText)
-            , str " "
             ]
 
 keybindEventHelpMarkdown :: (Either Text Text, Text, [Text]) -> Text
diff --git a/src/Draw/TabbedWindow.hs b/src/Draw/TabbedWindow.hs
--- a/src/Draw/TabbedWindow.hs
+++ b/src/Draw/TabbedWindow.hs
@@ -12,10 +12,10 @@
 import           Data.List ( intersperse )
 import qualified Graphics.Vty as Vty
 
+import           Draw.Util ( renderKeybindingHelp )
 import           Types
 import           Themes
 import           Types.KeyEvents
-import           Events.Keybindings ( getFirstDefaultBinding )
 
 -- | Render a tabbed window.
 drawTabbedWindow :: (Eq a, Show a)
@@ -36,13 +36,10 @@
 -- | Keybinding help to show at the bottom of a tabbed window.
 keybindingHelp :: Widget Name
 keybindingHelp =
-    let ppPair (label, evs) = hBox $ (intersperse (txt "/") $ ppEv <$> evs) <> [txt (":" <> label)]
-        ppEv ev = withDefAttr clientEmphAttr $ txt (ppBinding (getFirstDefaultBinding ev))
-        pairs = [ ("Switch tabs", [SelectNextTabEvent, SelectPreviousTabEvent])
-                , ("Scroll", [ScrollUpEvent, ScrollDownEvent, ScrollLeftEvent, ScrollRightEvent])
-                , ("Close", [CancelEvent])
+    let pairs = [ ("Switch tabs", [SelectNextTabEvent, SelectPreviousTabEvent])
+                , ("Scroll", [ScrollUpEvent, ScrollDownEvent, ScrollLeftEvent, ScrollRightEvent, PageLeftEvent, PageRightEvent])
                 ]
-    in hBox $ intersperse (txt "  ") $ ppPair <$> pairs
+    in hBox $ intersperse (txt "  ") $ (uncurry renderKeybindingHelp) <$> pairs
 
 -- | The scrollable tab bar to show at the top of a tabbed window.
 tabBar :: (Eq a, Show a)
diff --git a/src/Draw/ThemeListOverlay.hs b/src/Draw/ThemeListOverlay.hs
new file mode 100644
--- /dev/null
+++ b/src/Draw/ThemeListOverlay.hs
@@ -0,0 +1,53 @@
+{-# LANGUAGE OverloadedStrings #-}
+{-# LANGUAGE RecordWildCards #-}
+
+module Draw.ThemeListOverlay
+  ( drawThemeListOverlay
+  )
+where
+
+import           Prelude ()
+import           Prelude.MH
+
+import           Brick
+import qualified Brick.Widgets.List as L
+import           Brick.Widgets.Border ( hBorder )
+import           Brick.Widgets.Center ( hCenter )
+
+import           Draw.Main
+import           Draw.ListOverlay ( drawListOverlay, OverlayPosition(..) )
+import           Themes
+import           Types
+import           Types.KeyEvents ( ppBinding )
+import           Events.Keybindings
+
+
+drawThemeListOverlay :: ChatState -> [Widget Name]
+drawThemeListOverlay st =
+    let overlay = drawListOverlay (st^.csThemeListOverlay)
+                                  (const $ txt "Themes")
+                                  (const $ txt "No matching themes found.")
+                                  (const $ txt "Search built-in themes:")
+                                  renderInternalTheme
+                                  (Just footer)
+                                  OverlayUpperRight
+                                  50
+        footer = hBorder <=>
+                 (hCenter $ hBox [ enter
+                                 , txt $ ":choose theme  "
+                                 , close
+                                 , txt ":close"
+                                 ])
+        enter = emph $ txt $ ppBinding (getFirstDefaultBinding ActivateListItemEvent)
+        close = emph $ txt $ ppBinding (getFirstDefaultBinding CancelEvent)
+        emph = withDefAttr clientEmphAttr
+    in joinBorders overlay : drawMain True st
+
+renderInternalTheme :: Bool -> InternalTheme -> Widget Name
+renderInternalTheme foc it =
+    (if foc then forceAttr L.listSelectedFocusedAttr else id) $
+    (padRight Max $
+     withDefAttr clientEmphAttr $
+     txt $ internalThemeName it) <=>
+    (vLimit 2 $
+     (padLeft (Pad 2) $ txtWrap $ internalThemeDesc it) <=> fill ' ')
diff --git a/src/Draw/URLList.hs b/src/Draw/URLList.hs
--- a/src/Draw/URLList.hs
+++ b/src/Draw/URLList.hs
@@ -15,9 +15,10 @@
 
 import           Draw.Messages
 import           Draw.Util
-import           Markdown
+import           Draw.RichText
 import           Themes
 import           Types
+import           Types.RichText ( unURL )
 
 
 renderUrlList :: ChatState -> Widget Name
@@ -34,20 +35,23 @@
 
         urls = st^.csUrlList
 
+        me = myUsername st
+
         renderItem sel link =
           let time = link^.linkTime
           in attr sel $ vLimit 2 $
             (vLimit 1 $
-             hBox [ let u = maybe "" id (link^.linkUser.to (nameForUserRef st)) in colorUsername (myUsername st) u u
-                  , if link^.linkName == link^.linkURL
-                      then emptyWidget
-                      else (txt ": " <+> (renderText $ link^.linkName))
+             hBox [ let u = maybe "<server>" id (link^.linkUser.to (nameForUserRef st))
+                    in colorUsername me u u
+                  , case link^.linkLabel of
+                      Nothing -> emptyWidget
+                      Just label -> txt ": " <+> hBox (F.toList $ renderElementSeq me label)
                   , fill ' '
                   , renderDate st $ withServerTime time
                   , str " "
                   , renderTime st $ withServerTime time
                   ] ) <=>
-            (vLimit 1 (renderText $ link^.linkURL))
+            (vLimit 1 (renderText $ unURL $ link^.linkURL))
 
-        attr True = forceAttr "urlListSelectedAttr"
+        attr True = forceAttr urlListSelectedAttr
         attr False = id
diff --git a/src/Draw/UserListOverlay.hs b/src/Draw/UserListOverlay.hs
--- a/src/Draw/UserListOverlay.hs
+++ b/src/Draw/UserListOverlay.hs
@@ -16,7 +16,7 @@
 
 import           Draw.Main
 import           Draw.Util ( userSigilFromInfo )
-import           Draw.ListOverlay ( drawListOverlay )
+import           Draw.ListOverlay ( drawListOverlay, OverlayPosition(..) )
 import           Themes
 import           Types
 
@@ -26,6 +26,9 @@
     let overlay = drawListOverlay (st^.csUserListOverlay) userSearchScopeHeader
                                   userSearchScopeNoResults userSearchScopePrompt
                                   (renderUser (myUsername st))
+                                  Nothing
+                                  OverlayCenter
+                                  80
     in joinBorders overlay : drawMain False st
 
 userSearchScopePrompt :: UserSearchScope -> Widget Name
diff --git a/src/Draw/Util.hs b/src/Draw/Util.hs
--- a/src/Draw/Util.hs
+++ b/src/Draw/Util.hs
@@ -2,6 +2,7 @@
   ( withBrackets
   , renderTime
   , renderDate
+  , renderKeybindingHelp
   , insertDateMarkers
   , getDateFormat
   , mkChannelName
@@ -14,14 +15,18 @@
 import           Prelude.MH
 
 import           Brick
+import           Data.List ( intersperse )
 import qualified Data.Set as Set
 import qualified Data.Text as T
 import           Lens.Micro.Platform ( to )
 import           Network.Mattermost.Types
 
+import           Constants ( userSigil, normalChannelSigil )
 import           Themes
 import           TimeUtils
 import           Types
+import           Types.KeyEvents
+import           Events.Keybindings ( getFirstDefaultBinding )
 
 
 defaultTimeFormat :: Text
@@ -52,6 +57,11 @@
     if T.null fmt
     then emptyWidget
     else withDefAttr timeAttr (txt $ localTimeText fmt $ asLocalTime tz t)
+
+renderKeybindingHelp :: Text -> [KeyEvent] -> Widget Name
+renderKeybindingHelp label evs =
+  let ppEv ev = withDefAttr clientEmphAttr $ txt (ppBinding (getFirstDefaultBinding ev))
+  in hBox $ (intersperse (txt "/") $ ppEv <$> evs) <> [txt (":" <> label)]
 
 -- | Generates a local matterhorn-only client message that creates a
 -- date marker.  The server date is converted to a local time (via
diff --git a/src/Events.hs b/src/Events.hs
--- a/src/Events.hs
+++ b/src/Events.hs
@@ -22,6 +22,7 @@
 import           Network.Mattermost.WebSocket
 
 import           Connection
+import           Constants ( userSigil, normalChannelSigil )
 import           HelpTopics
 import           State.Channels
 import           State.Common
@@ -39,6 +40,7 @@
 import           Events.LeaveChannelConfirm
 import           Events.Main
 import           Events.MessageSelect
+import           Events.ThemeListOverlay
 import           Events.PostListOverlay
 import           Events.ShowHelp
 import           Events.UrlSelect
@@ -47,6 +49,7 @@
 import           Events.ReactionEmojiListOverlay
 import           Events.TabbedWindow
 import           Events.ManageAttachments
+import           Events.EditNotifyPrefs
 
 
 onEvent :: ChatState -> BrickEvent Name MHEvent -> EventM Name (Next ChatState)
@@ -191,6 +194,7 @@
         MessageSelect              -> onEventMessageSelect e
         MessageSelectDeleteConfirm -> onEventMessageSelectDeleteConfirm e
         DeleteChannelConfirm       -> onEventDeleteChannelConfirm e
+        ThemeListOverlay           -> onEventThemeListOverlay e
         PostListOverlay _          -> onEventPostListOverlay e
         UserListOverlay            -> onEventUserListOverlay e
         ChannelListOverlay         -> onEventChannelListOverlay e
@@ -198,6 +202,7 @@
         ViewMessage                -> void $ handleTabbedWindowEvent (csViewedMessage.singular _Just._2) e
         ManageAttachments          -> onEventManageAttachments e
         ManageAttachmentsBrowseFiles -> onEventManageAttachments e
+        EditNotifyPrefs            -> void $ onEventEditNotifyPrefs e
 
 globalKeybindings :: KeyConfig -> KeyHandlerMap
 globalKeybindings = mkKeybindings globalKeyHandlers
@@ -335,6 +340,14 @@
             | Just cId <- webChannelId (weBroadcast we) -> handleChannelInvite cId
             | otherwise -> return ()
 
+        WMChannelMemberUpdated
+            | Just channelMember <- wepChannelMember $ weData we ->
+                  when (channelMemberUserId channelMember == myId) $
+                      updateChannelNotifyProps
+                      (channelMemberChannelId channelMember)
+                      (channelMemberNotifyProps channelMember)
+            | otherwise -> return ()
+
         -- We are pretty sure we should do something about these:
         WMAddedToTeam -> return ()
 
@@ -344,7 +357,6 @@
         WMTeamDeleted -> return ()
         WMUserUpdated -> return ()
         WMLeaveTeam -> return ()
-        WMChannelMemberUpdated {} -> return ()
 
         -- We deliberately ignore these events:
         WMChannelCreated -> return ()
diff --git a/src/Events/EditNotifyPrefs.hs b/src/Events/EditNotifyPrefs.hs
new file mode 100644
--- /dev/null
+++ b/src/Events/EditNotifyPrefs.hs
@@ -0,0 +1,48 @@
+module Events.EditNotifyPrefs
+    ( onEventEditNotifyPrefs
+    , editNotifyPrefsKeybindings
+    , editNotifyPrefsKeyHandlers
+    )
+where
+
+import           Prelude ()
+import           Prelude.MH
+
+import           Brick
+import           Brick.Forms (handleFormEvent, formState)
+import           Data.Maybe (fromJust)
+import qualified Graphics.Vty as V
+import qualified Network.Mattermost.Endpoints as MM
+
+import           Lens.Micro.Platform (_Just, (.=), singular)
+
+import           Types
+import           Types.KeyEvents
+import           Events.Keybindings
+import           State.NotifyPrefs
+import           State.Async
+
+onEventEditNotifyPrefs :: V.Event -> MH Bool
+onEventEditNotifyPrefs =
+    let fallback e = do
+            form <- use (csNotifyPrefs.singular _Just)
+            updatedForm <- mh $ handleFormEvent (VtyEvent e) form
+            csNotifyPrefs .= Just updatedForm
+    in handleKeyboardEvent editNotifyPrefsKeybindings fallback
+
+editNotifyPrefsKeybindings :: KeyConfig -> KeyHandlerMap
+editNotifyPrefsKeybindings = mkKeybindings editNotifyPrefsKeyHandlers
+
+editNotifyPrefsKeyHandlers :: [KeyEventHandler]
+editNotifyPrefsKeyHandlers =
+    [ mkKb CancelEvent "Close channel notification preferences" exitEditNotifyPrefsMode
+    , mkKb FormSubmitEvent "Save channel notification preferences" $ do
+        st <- use id
+        let form = fromJust $ st^.csNotifyPrefs
+            cId = st^.csCurrentChannelId
+
+        doAsyncChannelMM Preempt cId
+          (\s _ -> MM.mmUpdateChannelNotifications cId (myUserId st) (formState form) s)
+          (\_ _ -> Nothing)
+        exitEditNotifyPrefsMode
+    ]
diff --git a/src/Events/Keybindings.hs b/src/Events/Keybindings.hs
--- a/src/Events/Keybindings.hs
+++ b/src/Events/Keybindings.hs
@@ -149,6 +149,7 @@
 defaultBindings ev =
   let meta binding = binding { kbMods = Vty.MMeta : kbMods binding }
       ctrl binding = binding { kbMods = Vty.MCtrl : kbMods binding }
+      shift binding = binding { kbMods = Vty.MShift : kbMods binding }
       kb k = Binding { kbMods = [], kbKey = k }
       key c = Binding { kbMods = [], kbKey = Vty.KChar c }
       fn n = Binding { kbMods = [], kbKey = Vty.KFun n }
@@ -183,8 +184,11 @@
         ScrollRightEvent              -> [ kb Vty.KRight ]
         PageUpEvent                   -> [ kb Vty.KPageUp ]
         PageDownEvent                 -> [ kb Vty.KPageDown ]
+        PageLeftEvent                 -> [ shift (kb Vty.KLeft) ]
+        PageRightEvent                -> [ shift (kb Vty.KRight) ]
         ScrollTopEvent                -> [ kb Vty.KHome ]
         ScrollBottomEvent             -> [ kb Vty.KEnd ]
+        SelectOldestMessageEvent      -> [ shift (kb Vty.KHome) ]
         SelectUpEvent                 -> [ key 'k', kb Vty.KUp ]
         SelectDownEvent               -> [ key 'j', kb Vty.KDown ]
         ActivateListItemEvent         -> [ kb Vty.KEnter ]
@@ -220,6 +224,7 @@
         EditorHomeEvent               -> [ kb Vty.KHome ]
         EditorEndEvent                -> [ kb Vty.KEnd ]
         EditorYankEvent               -> [ ctrl (key 'y') ]
+        FormSubmitEvent               -> [ kb Vty.KEnter ]
 
 -- | Given a configuration, we want to check it for internal consistency
 -- (i.e. that a given keybinding isn't associated with multiple events
diff --git a/src/Events/Main.hs b/src/Events/Main.hs
--- a/src/Events/Main.hs
+++ b/src/Events/Main.hs
@@ -49,7 +49,7 @@
 
     , mkKb
         InvokeEditorEvent
-        "Invoke *$EDITOR* to edit the current message"
+        "Invoke `$EDITOR` to edit the current message"
         invokeExternalEditor
 
     , mkKb
@@ -95,7 +95,7 @@
     , mkKb PageUpEvent "Page up in the channel message list (enters message select mode)" $ do
              beginMessageSelect
 
-    , mkKb ScrollTopEvent "Scroll to top of channel message list" $ do
+    , mkKb SelectOldestMessageEvent "Scroll to top of channel message list" $ do
              beginMessageSelect
              messageSelectFirst
 
diff --git a/src/Events/ManageAttachments.hs b/src/Events/ManageAttachments.hs
--- a/src/Events/ManageAttachments.hs
+++ b/src/Events/ManageAttachments.hs
@@ -3,6 +3,7 @@
 module Events.ManageAttachments
   ( onEventManageAttachments
   , attachmentListKeybindings
+  , attachmentBrowseKeyHandlers
   , attachmentBrowseKeybindings
   , attachmentListKeyHandlers
   )
@@ -12,7 +13,6 @@
 import           Prelude.MH
 
 import qualified Control.Exception as E
-import           Control.Monad ( void )
 import qualified Brick.Widgets.FileBrowser as FB
 import qualified Brick.Widgets.List as L
 import qualified Data.ByteString as BS
@@ -61,7 +61,10 @@
     ]
 
 attachmentBrowseKeybindings :: KeyConfig -> KeyHandlerMap
-attachmentBrowseKeybindings = mkKeybindings
+attachmentBrowseKeybindings = mkKeybindings attachmentBrowseKeyHandlers
+
+attachmentBrowseKeyHandlers :: [KeyEventHandler]
+attachmentBrowseKeyHandlers =
     [ mkKb CancelEvent "Cancel attachment file browse"
       cancelAttachmentBrowse
     , mkKb AttachmentOpenEvent "Open the selected file using the URL open command"
diff --git a/src/Events/ThemeListOverlay.hs b/src/Events/ThemeListOverlay.hs
new file mode 100644
--- /dev/null
+++ b/src/Events/ThemeListOverlay.hs
@@ -0,0 +1,30 @@
+module Events.ThemeListOverlay where
+
+import           Prelude ()
+import           Prelude.MH
+
+import qualified Graphics.Vty as Vty
+
+import           Events.Keybindings
+import           State.ThemeListOverlay
+import           State.ListOverlay
+import           Types
+
+
+onEventThemeListOverlay :: Vty.Event -> MH ()
+onEventThemeListOverlay =
+    void . onEventListOverlay csThemeListOverlay themeListOverlayKeybindings
+
+-- | The keybindings we want to use while viewing a user list overlay
+themeListOverlayKeybindings :: KeyConfig -> KeyHandlerMap
+themeListOverlayKeybindings = mkKeybindings themeListOverlayKeyHandlers
+
+themeListOverlayKeyHandlers :: [KeyEventHandler]
+themeListOverlayKeyHandlers =
+    [ mkKb CancelEvent "Close the theme list" (exitListOverlay csThemeListOverlay)
+    , mkKb SearchSelectUpEvent "Select the previous theme" themeListSelectUp
+    , mkKb SearchSelectDownEvent "Select the next theme" themeListSelectDown
+    , mkKb PageDownEvent "Page down in the theme list" themeListPageDown
+    , mkKb PageUpEvent "Page up in the theme list" themeListPageUp
+    , mkKb ActivateListItemEvent "Switch to the selected color theme" (listOverlayActivateCurrent csThemeListOverlay)
+    ]
diff --git a/src/Login.hs b/src/Login.hs
--- a/src/Login.hs
+++ b/src/Login.hs
@@ -81,7 +81,7 @@
 import           Network.Mattermost.Exceptions ( LoginFailureException(..) )
 import           Network.Mattermost.Endpoints ( mmGetUser, mmGetLimitedClientConfiguration, mmLogin )
 
-import           Markdown
+import           Draw.RichText
 import           Themes ( clientEmphAttr )
 import           Types ( ConnectionInfo(..)
                        , ciPassword, ciUsername, ciHostname, ciUrlPath
@@ -223,28 +223,35 @@
 
 
 
--- | Searches prefixes of the given URL to determine Mattermost API URL path and team name
+-- | Searches prefixes of the given URL to determine Mattermost API URL
+-- path and team name
 findConnectionData :: ConnectionInfo -> IO (Either SomeException (ConnectionData, Maybe Text))
 findConnectionData connInfo = startSearch
-
   where
     components = filter (not . T.null) (T.split ('/'==) (connInfo^.ciUrlPath))
 
-    -- the candidates list is never empty because inits never returns an empty list
+    -- the candidates list is never empty because inits never returns an
+    -- empty list
     primary:alternatives =
         reverse
-        [ (T.intercalate "/" l, listToMaybe r) | (l,r) <- zip (inits components) (tails components) ]
+        [ (T.intercalate "/" l, listToMaybe r)
+        | (l,r) <- zip (inits components) (tails components)
+        ]
 
-    tryCandidate :: (Text, Maybe Text) -> IO (Either SomeException (ConnectionData, Maybe Text))
+    tryCandidate :: (Text, Maybe Text)
+                 -> IO (Either SomeException (ConnectionData, Maybe Text))
     tryCandidate (path, team) =
-       do cd  <- initConnectionData (connInfo^.ciHostname) (fromIntegral (connInfo^.ciPort)) path (connInfo^.ciType) poolCfg
+       do cd  <- initConnectionData (connInfo^.ciHostname)
+                                    (fromIntegral (connInfo^.ciPort))
+                                    path (connInfo^.ciType) poolCfg
           res <- try (mmGetLimitedClientConfiguration cd)
           pure $! case res of
                     Left e  -> Left e
                     Right{} -> Right (cd, team)
 
-    -- This code prefers to report the error from the URL corresponding to what the user
-    -- actually provided. Errors from derived URLs are lost in favor of this first error.
+    -- This code prefers to report the error from the URL corresponding
+    -- to what the user actually provided. Errors from derived URLs are
+    -- lost in favor of this first error.
     startSearch =
       do res1 <- tryCandidate primary
          case res1 of
diff --git a/src/Markdown.hs b/src/Markdown.hs
deleted file mode 100644
--- a/src/Markdown.hs
+++ /dev/null
@@ -1,634 +0,0 @@
-{-# LANGUAGE LambdaCase #-}
-{-# LANGUAGE MultiWayIf       #-}
-{-# LANGUAGE ParallelListComp #-}
-{-# LANGUAGE RecordWildCards  #-}
-{-# LANGUAGE ViewPatterns     #-}
-
-module Markdown
-  ( MessageData(..)
-  , renderMessage
-  , renderText
-  , renderText'
-  , cursorSentinel
-  , addEllipsis
-  , findVerbatimChunk
-  )
-where
-
-import           Prelude ()
-import           Prelude.MH
-
-import           Brick ( (<+>), Widget, textWidth, hLimit, imageL
-                       , raw, render, Size(..), Widget(..)
-                       )
-import qualified Brick as B
-import qualified Brick.Widgets.Border as B
-import qualified Brick.Widgets.Skylighting as BS
-import qualified Cheapskate as C
-import           Cheapskate.Types ( Block
-                                  , Blocks
-                                  , Inlines
-                                  , ListType
-                                  )
-import qualified Data.Foldable as F
-import qualified Data.Map.Strict as Map
-import           Data.Monoid (First(..))
-import qualified Data.Sequence as Seq
-import           Data.Sequence ( ViewL(..)
-                               , ViewR(..)
-                               , (<|)
-                               , (|>)
-                               , viewl
-                               , viewr)
-import qualified Data.Sequence as S
-import qualified Data.Set as Set
-import qualified Data.Text as T
-import qualified Graphics.Vty as V
-import qualified Skylighting.Core as Sky
-
-import           Network.Mattermost.Lenses ( postEditAtL, postCreateAtL )
-import           Network.Mattermost.Types ( ServerTime(..) )
-
-import           Themes
-import           Types ( Name, HighlightSet(..), userSigil, normalChannelSigil )
-import           Types.Messages
-import           Types.Posts
-import           Types.UserNames ( isNameFragment, takeWhileNameFragment )
-
-
-emptyHSet :: HighlightSet
-emptyHSet = HighlightSet Set.empty Set.empty mempty
-
-omittedUsernameType :: MessageType -> Bool
-omittedUsernameType = \case
-  CP Join -> True
-  CP Leave -> True
-  CP TopicChange -> True
-  _ -> False
-
-
--- The special string we use to indicate the placement of a styled
--- indication that a message has been edited.
-editMarkingSentinel :: Text
-editMarkingSentinel = "#__mh_edit"
-
--- The special string we use to indicate the placement of a styled
--- indication that a message has been edited recently.
-editRecentlyMarkingSentinel :: Text
-editRecentlyMarkingSentinel = "#__mh_edit_r"
-
--- The actual user-facing text that we render in place of the edit
--- marking sentinel.
-editMarking :: Text
-editMarking = "(edited)"
-
--- Add the edit sentinel to the end of the last block in the sequence.
--- If the last block is a paragraph, append it to that paragraph.
--- Otherwise, append a new block so it appears beneath the last
--- block-level element.
-addEditSentinel :: Text -> Blocks -> Blocks
-addEditSentinel s bs =
-    case viewr bs of
-        EmptyR -> bs
-        (rest :> b) -> rest <> appendEditSentinel s b
-
-appendEditSentinel :: Text -> Block -> Blocks
-appendEditSentinel sentinel b =
-    let s = C.Para (S.singleton m)
-        m = C.Str sentinel
-    in case b of
-        C.Para is -> S.singleton $ C.Para (is |> C.Str " " |> m)
-        _ -> S.fromList [b, s]
-
--- | A bundled structure that includes all the information necessary
--- to render a given message
-data MessageData =
-    MessageData { mdEditThreshold :: Maybe ServerTime
-                -- ^ If specified, any messages edited before this point
-                -- in time are not indicated as edited.
-                , mdShowOlderEdits :: Bool
-                -- ^ Indicates whether "edited" markers should be shown
-                -- for old messages (i.e., ignore the mdEditThreshold
-                -- value).
-                , mdShowReactions :: Bool
-                -- ^ Whether to render reactions.
-                , mdMessage :: Message
-                -- ^ The message to render.
-                , mdUserName :: Maybe Text
-                -- ^ The username of the message's author, if any. This
-                -- is passed here rather than obtaining from the message
-                -- because we need to do lookups in the ChatState to
-                -- compute this, and we don't pass the ChatState into
-                -- renderMessage.
-                , mdParentMessage :: Maybe Message
-                -- ^ The parent message of this message, if any.
-                , mdParentUserName :: Maybe Text
-                -- ^ The author of the parent message, if any.
-                , mdThreadState :: ThreadState
-                -- ^ The thread state of this message.
-                , mdRenderReplyParent :: Bool
-                -- ^ Whether to render the parent message.
-                , mdHighlightSet :: HighlightSet
-                -- ^ The highlight set to use to highlight usernames,
-                -- channel names, etc.
-                , mdIndentBlocks :: Bool
-                -- ^ Whether to indent the message underneath the
-                -- author's name (True) or just display it to the right
-                -- of the author's name (False).
-                , mdMessageWidthLimit :: Maybe Int
-                -- ^ A width override to use to wrap non-code blocks. If
-                -- unspecified, all blocks in the message will be
-                -- wrapped and truncated at the width specified by the
-                -- rendering context. If specified, all non-code blocks
-                -- will be wrapped at this width and code blocks will be
-                -- rendered using the context's width.
-                , mdMyUsername :: Text
-                -- ^ The username of the user running Matterhorn.
-                }
-
--- | renderMessage performs markdown rendering of the specified message.
-renderMessage :: MessageData -> Widget Name
-renderMessage md@MessageData { mdMessage = msg, .. } =
-    let msgUsr = case mdUserName of
-          Just u -> if omittedUsernameType (msg^.mType) then Nothing else Just u
-          Nothing -> Nothing
-        botElem = if isBotMessage msg then B.txt "[BOT]" else B.emptyWidget
-        nameElems = case msgUsr of
-          Just un
-            | isEmote msg ->
-                [ B.withDefAttr pinnedMessageIndicatorAttr $ B.txt $ if msg^.mPinned then "[PIN]" else ""
-                , B.txt $ (if msg^.mFlagged then "[!] " else "") <> "*"
-                , colorUsername mdMyUsername un un
-                , botElem
-                , B.txt " "
-                ]
-            | otherwise ->
-                [ B.withDefAttr pinnedMessageIndicatorAttr $ B.txt $ if msg^.mPinned then "[PIN] " else ""
-                , colorUsername mdMyUsername un un
-                , botElem
-                , B.txt $ (if msg^.mFlagged then "[!]" else "") <> ": "
-                ]
-          Nothing -> []
-
-        -- Use the editing threshold to determine whether to append an
-        -- editing indication to this message.
-        maybeAugment bs = case msg^.mOriginalPost of
-            Nothing -> bs
-            Just p ->
-                if p^.postEditAtL > p^.postCreateAtL
-                then case mdEditThreshold of
-                    Just cutoff | p^.postEditAtL >= cutoff ->
-                        addEditSentinel editRecentlyMarkingSentinel bs
-                    _ -> if mdShowOlderEdits
-                         then addEditSentinel editMarkingSentinel bs
-                         else bs
-                else bs
-
-        augmentedText = maybeAugment $ msg^.mText
-        msgWidget =
-            vBox $ (layout mdHighlightSet mdMessageWidthLimit nameElems augmentedText . viewl) augmentedText :
-                   catMaybes [msgAtch, msgReac]
-        replyIndent = B.Widget B.Fixed B.Fixed $ do
-            ctx <- B.getContext
-            -- NB: The amount subtracted here must be the total padding
-            -- added below (pad 1 + vBorder)
-            w <- B.render $ B.hLimit (ctx^.B.availWidthL - 2) msgWidget
-            B.render $ B.vLimit (V.imageHeight $ w^.B.imageL) $
-                B.padRight (B.Pad 1) B.vBorder B.<+> (B.Widget B.Fixed B.Fixed $ return w)
-        msgAtch = if Seq.null (msg^.mAttachments)
-          then Nothing
-          else Just $ B.withDefAttr clientMessageAttr $ vBox
-                 [ B.txt ("  [attached: `" <> a^.attachmentName <> "`]")
-                 | a <- toList (msg^.mAttachments)
-                 ]
-        msgReac = if Map.null (msg^.mReactions) || (not mdShowReactions)
-          then Nothing
-          else let renderR e us =
-                       let n = Set.size us
-                       in if | n == 1    -> " [" <> e <> "]"
-                             | n > 1     -> " [" <> e <> " " <> T.pack (show n) <> "]"
-                             | otherwise -> ""
-                   reactionMsg = Map.foldMapWithKey renderR (msg^.mReactions)
-               in Just $ B.withDefAttr emojiAttr $ B.txt ("   " <> reactionMsg)
-        withParent p =
-            case mdThreadState of
-                NoThread -> msgWidget
-                InThreadShowParent -> p B.<=> replyIndent
-                InThread -> replyIndent
-    in if not mdRenderReplyParent
-       then msgWidget
-       else case msg^.mInReplyToMsg of
-          NotAReply -> msgWidget
-          InReplyTo _ ->
-              case mdParentMessage of
-                  Nothing -> withParent (B.str "[loading...]")
-                  Just pm ->
-                      let parentMsg = renderMessage md
-                            { mdShowOlderEdits    = False
-                            , mdMessage           = pm
-                            , mdUserName          = mdParentUserName
-                            , mdParentMessage     = Nothing
-                            , mdRenderReplyParent = False
-                            , mdIndentBlocks      = False
-                            }
-                      in withParent (addEllipsis $ B.forceAttr replyParentAttr parentMsg)
-
-    where
-        layout :: HighlightSet -> Maybe Int -> [Widget Name] -> Blocks -> ViewL Block -> Widget Name
-        layout hs w nameElems bs xs | length xs > 1     = multiLnLayout hs w nameElems bs
-        layout hs w nameElems bs (C.Blockquote {} :< _) = multiLnLayout hs w nameElems bs
-        layout hs w nameElems bs (C.CodeBlock {} :< _)  = multiLnLayout hs w nameElems bs
-        layout hs w nameElems bs (C.HtmlBlock {} :< _)  = multiLnLayout hs w nameElems bs
-        layout hs w nameElems bs (C.List {} :< _)       = multiLnLayout hs w nameElems bs
-        layout hs w nameElems bs (C.Para inlns :< _)
-            | F.any breakCheck inlns                    = multiLnLayout hs w nameElems bs
-        layout hs w nameElems bs _                      = nameNextToMessage hs w nameElems bs
-
-        multiLnLayout hs w nameElems bs =
-            if mdIndentBlocks
-               then vBox [ hBox nameElems
-                         , hBox [B.txt "  ", renderMarkdown mdMyUsername hs ((subtract 2) <$> w) bs]
-                         ]
-               else nameNextToMessage hs w nameElems bs
-
-        nameNextToMessage hs w nameElems bs =
-            Widget Fixed Fixed $ do
-                nameResult <- render $ hBox nameElems
-                let newW = subtract (V.imageWidth (nameResult^.imageL)) <$> w
-                render $ hBox [raw (nameResult^.imageL), renderMarkdown mdMyUsername hs newW bs]
-
-        breakCheck C.LineBreak = True
-        breakCheck C.SoftBreak = True
-        breakCheck _ = False
-
-addEllipsis :: Widget a -> Widget a
-addEllipsis w = B.Widget (B.hSize w) (B.vSize w) $ do
-    ctx <- B.getContext
-    let aw = ctx^.B.availWidthL
-    result <- B.render w
-    let withEllipsis = (B.hLimit (aw - 3) $ B.vLimit 1 $ (B.Widget B.Fixed B.Fixed $ return result)) <+>
-                       B.str "..."
-    if (V.imageHeight (result^.B.imageL) > 1) || (V.imageWidth (result^.B.imageL) == aw) then
-        B.render withEllipsis else
-        return result
-
--- Cursor sentinel for tracking the user's cursor position in previews.
-cursorSentinel :: Char
-cursorSentinel = '‸'
-
--- Render markdown with username highlighting
-renderMarkdown :: Text -> HighlightSet -> Maybe Int -> Blocks -> Widget a
-renderMarkdown curUser hSet w =
-  B.vBox . toList . fmap (blockToWidget curUser hSet w) . addBlankLines
-
--- Add blank lines only between adjacent elements of the same type, to
--- save space
-addBlankLines :: Seq Block -> Seq Block
-addBlankLines = go' . viewl
-  where go' EmptyL = S.empty
-        go' (x :< xs) = go x (viewl xs)
-        go a@C.Para {} (b@C.Para {} :< rs) =
-             a <| blank <| go b (viewl rs)
-        go a@C.Header {} (b@C.Header {} :< rs) =
-             a <| blank <| go b (viewl rs)
-        go a@C.Blockquote {} (b@C.Blockquote {} :< rs) =
-             a <| blank <| go b (viewl rs)
-        go a@C.List {} (b@C.List {} :< rs) =
-             a <| blank <| go b (viewl rs)
-        go a@C.CodeBlock {} (b@C.CodeBlock {} :< rs) =
-             a <| blank <| go b (viewl rs)
-        go a@C.HtmlBlock {} (b@C.HtmlBlock {} :< rs) =
-             a <| blank <| go b (viewl rs)
-        go x (y :< rs) = x <| go y (viewl rs)
-        go x (EmptyL) = S.singleton x
-        blank = C.Para (S.singleton (C.Str " "))
-
--- Render text to markdown without username highlighting
-renderText :: Text -> Widget a
-renderText txt = renderText' "" emptyHSet txt
-
-renderText' :: Text -> HighlightSet -> Text -> Widget a
-renderText' curUser hSet txt = renderMarkdown curUser hSet Nothing bs
-  where C.Doc _ bs = C.markdown C.def txt
-
-vBox :: F.Foldable f => f (Widget a) -> Widget a
-vBox = B.vBox . toList
-
-hBox :: F.Foldable f => f (Widget a) -> Widget a
-hBox = B.hBox . toList
-
-header :: Int -> Widget a
-header n = B.txt (T.replicate n "#")
-
-maybeHLimit :: Maybe Int -> Widget a -> Widget a
-maybeHLimit Nothing w = w
-maybeHLimit (Just i) w = hLimit i w
-
-blockToWidget :: Text -> HighlightSet -> Maybe Int -> Block -> Widget a
-blockToWidget curUser hSet w (C.Para is) =
-    toInlineChunk curUser w is hSet
-blockToWidget curUser hSet w (C.Header n is) =
-    B.withDefAttr clientHeaderAttr $
-      hBox [B.padRight (B.Pad 1) $ header n, toInlineChunk curUser (subtract 1 <$> w) is hSet]
-blockToWidget curUser hSet w (C.Blockquote is) =
-    maybeHLimit w $
-    addQuoting (vBox $ fmap (blockToWidget curUser hSet w) is)
-blockToWidget curUser hSet w (C.List _ l bs) =
-    maybeHLimit w $
-    blocksToList curUser l w bs hSet
-blockToWidget _ hSet _ (C.CodeBlock ci tx) =
-    let f = maybe rawCodeBlockToWidget (codeBlockToWidget (hSyntaxMap hSet)) mSyntax
-        mSyntax = Sky.lookupSyntax (C.codeLang ci) (hSyntaxMap hSet)
-    in f tx
-blockToWidget _ _ w (C.HtmlBlock txt) =
-    maybeHLimit w $
-    textWithCursor txt
-blockToWidget _ _ w (C.HRule) =
-    maybeHLimit w $
-    B.vLimit 1 (B.fill '*')
-
-quoteChar :: Char
-quoteChar = '>'
-
-addQuoting :: B.Widget n -> B.Widget n
-addQuoting w =
-    B.Widget B.Fixed (B.vSize w) $ do
-        ctx <- B.getContext
-        childResult <- B.render $ B.hLimit (ctx^.B.availWidthL - 2) w
-
-        let quoteBorder = B.raw $ V.charFill (ctx^.B.attrL) quoteChar 1 height
-            height = V.imageHeight $ childResult^.B.imageL
-
-        B.render $ B.hBox [ B.padRight (B.Pad 1) quoteBorder
-                          , B.Widget B.Fixed B.Fixed $ return childResult
-                          ]
-
-codeBlockToWidget :: Sky.SyntaxMap -> Sky.Syntax -> Text -> Widget a
-codeBlockToWidget syntaxMap syntax tx =
-    let result = Sky.tokenize cfg syntax tx
-        cfg = Sky.TokenizerConfig syntaxMap False
-    in case result of
-        Left _ -> rawCodeBlockToWidget tx
-        Right tokLines ->
-            let padding = B.padLeftRight 1 (B.vLimit (length tokLines) B.vBorder)
-            in (B.txt $ "[" <> Sky.sName syntax <> "]") B.<=>
-               (padding <+> BS.renderRawSource textWithCursor tokLines)
-
-rawCodeBlockToWidget :: Text -> Widget a
-rawCodeBlockToWidget tx =
-    B.withDefAttr codeAttr $
-        let padding = B.padLeftRight 1 (B.vLimit (length theLines) B.vBorder)
-            theLines = expandEmpty <$> T.lines tx
-            expandEmpty "" = " "
-            expandEmpty s  = s
-        in padding <+> (B.vBox $ textWithCursor <$> theLines)
-
-toInlineChunk :: Text -> Maybe Int -> Inlines -> HighlightSet -> Widget a
-toInlineChunk curUser w is hSet = B.Widget B.Fixed B.Fixed $ do
-  ctx <- B.getContext
-  let width = fromMaybe (ctx^.B.availWidthL) w
-      fs    = toFragments hSet is
-      ws    = fmap (gatherWidgets curUser) (split width hSet fs)
-  B.render (vBox (fmap hBox ws))
-
-blocksToList :: Text -> ListType -> Maybe Int -> [Blocks] -> HighlightSet -> Widget a
-blocksToList curUser lt w bs hSet = vBox
-  [ B.txt i <+> (vBox (fmap (blockToWidget curUser hSet w) b))
-  | b <- bs | i <- is ]
-  where is = case lt of
-          C.Bullet _ -> repeat ("• ")
-          C.Numbered C.PeriodFollowing s ->
-            [ T.pack (show (n :: Int)) <> ". " | n <- [s..] ]
-          C.Numbered C.ParenFollowing s ->
-            [ T.pack (show (n :: Int)) <> ") " | n <- [s..] ]
-
--- We want to do word-wrapping, but for that we want a linear
--- sequence of chunks we can break up. The typical Markdown
--- format doesn't fit the bill: when it comes to bold or italic
--- bits, we'd have treat it all as one. This representation is
--- more amenable to splitting up those bits.
-data Fragment = Fragment
-  { fTextual :: TextFragment
-  , _fStyle  :: FragmentStyle
-  } deriving (Show, Eq)
-
-data TextFragment
-  = TStr Text
-  | TSpace
-  | TSoftBreak
-  | TLineBreak
-  | TLink Text
-  | TRawHtml Text
-  | TEditSentinel
-  | TEditRecentlySentinel
-  | TComplex (Seq Fragment)
-    deriving (Show, Eq)
-
-data FragmentStyle
-  = Normal
-  | Emph
-  | Strong
-  | Code
-  | User Text
-  | Link Text
-  | Emoji
-  | Channel
-  | Edited
-  | EditedRecently
-    deriving (Eq, Show)
-
-unsafeGetStr :: C.Inline -> Text
-unsafeGetStr (C.Str t) = t
-unsafeGetStr _ = error "BUG: unsafeGetStr called on non-Str Inline"
-
-toFragments :: HighlightSet -> Inlines -> Seq Fragment
-toFragments hSet = go Normal
-  where go n c = case viewl c of
-          C.Str t :< xs | t == editMarkingSentinel ->
-            Fragment TEditSentinel Edited <| go n xs
-          C.Str t :< xs | t == editRecentlyMarkingSentinel ->
-            Fragment TEditRecentlySentinel EditedRecently <| go n xs
-          C.Str t :< xs | userSigil `T.isPrefixOf` t ->
-            let (uFrags, rest) = takeWhileNameFragment $ F.toList xs
-                t' = T.concat $ t : (unsafeGetStr <$> F.toList uFrags)
-                u = T.drop 1 t'
-                sty = if u `Set.member` (hUserSet hSet)
-                      then User u
-                      else n
-            in Fragment (TStr t') sty <| go n (S.fromList rest)
-          C.Str t :< xs | normalChannelSigil `T.isPrefixOf` t ->
-            let (cFrags, rest) = S.spanl isNameFragment xs
-                cn = T.concat $ t : (unsafeGetStr <$> F.toList cFrags)
-                sty = if cn `Set.member` (hChannelSet hSet)
-                      then Channel
-                      else n
-            in Fragment (TStr cn) sty <| go n rest
-          C.Str t :< xs ->
-            Fragment (TStr t) n <| go n xs
-          C.Space :< xs ->
-            Fragment TSpace n <| go n xs
-          C.SoftBreak :< xs ->
-            Fragment TSoftBreak n <| go n xs
-          C.LineBreak :< xs ->
-            Fragment TLineBreak n <| go n xs
-          C.Link label url _ :< xs ->
-            case toList label of
-              [C.Str s] | s == url -> Fragment (TLink url) (Link url) <| go n xs
-              _                    -> Fragment (TComplex $ toFragments hSet label) (Link url) <| go n xs
-          C.RawHtml t :< xs ->
-            Fragment (TRawHtml t) n <| go n xs
-          C.Code t :< xs ->
-            let ts  = [ Fragment frag Code
-                      | wd <- T.split (== ' ') t
-                      , frag <- case wd of
-                          "" -> [TSpace]
-                          _  -> [TSpace, TStr wd]
-                      ]
-                ts' = case ts of
-                  (Fragment TSpace _:rs) -> rs
-                  _                      -> ts
-            in S.fromList ts' <> go n xs
-          C.Emph is :< xs ->
-            go Emph is <> go n xs
-          C.Strong is :< xs ->
-            go Strong is <> go n xs
-          C.Image altIs url _ :< xs ->
-            Fragment (TStr ("[image" <> altInlinesString altIs <> "]")) (Link url) <| go n xs
-          C.Entity t :< xs ->
-            Fragment (TStr t) (Link t) <| go n xs
-          EmptyL -> S.empty
-
-data SplitState = SplitState
-  { splitChunks  :: Seq (Seq Fragment)
-  , splitCurrCol :: Int
-  }
-
-separate :: HighlightSet -> Seq Fragment -> Seq Fragment
-separate hSet sq = case viewl sq of
-  Fragment (TStr s) n :< xs -> gatherStrings s n xs
-  Fragment x n :< xs        -> Fragment x n <| separate hSet xs
-  EmptyL                    -> S.empty
-  where HighlightSet { hUserSet = uSet, hChannelSet = cSet } = hSet
-        gatherStrings s n rs =
-          let s' = removeCursor s
-          in case viewl rs of
-            _ | (userSigil `T.isPrefixOf` s' && (T.toLower (T.drop 1 s') `Set.member` uSet)) ->
-                buildString s n <| separate hSet rs
-            _ | (normalChannelSigil `T.isPrefixOf` s' && (T.drop 1 s' `Set.member` cSet)) ->
-                buildString s n <| separate hSet rs
-            Fragment (TStr s'') _ :< _
-              | s'' == userSigil || s'' == normalChannelSigil ->
-                buildString s n <| separate hSet rs
-            Fragment (TStr s'') n' :< xs
-              | n == n' -> gatherStrings (s <> s'') n xs
-            Fragment _ _ :< _ -> buildString s n <| separate hSet rs
-            EmptyL -> S.singleton (buildString s n)
-        buildString s n =
-            let s' = removeCursor s
-            in if | n == Code -> Fragment (TStr s) n
-                  | ":" `T.isPrefixOf` s' &&
-                    ":" `T.isSuffixOf` s' &&
-                    textWidth s' > 2 ->
-                      Fragment (TStr s) Emoji
-                  | Just uname <- userSigil `T.stripPrefix` removeCursor s
-                    , removeCursor (T.toLower uname) `Set.member` uSet ->
-                      Fragment (TStr s) (User uname)
-                  | normalChannelSigil `T.isPrefixOf` (removeCursor s) &&
-                    (T.drop 1 (removeCursor s) `Set.member` cSet) ->
-                      Fragment (TStr s) Channel
-                  | otherwise -> Fragment (TStr s) n
-
-removeCursor :: Text -> Text
-removeCursor = T.filter (/= cursorSentinel)
-
-split :: Int -> HighlightSet -> Seq Fragment -> Seq (Seq Fragment)
-split maxCols hSet = splitChunks
-                          . go (SplitState (S.singleton S.empty) 0)
-                          . separate hSet
-  where go st (viewl-> f :< fs) = go st' fs
-          where st' =
-                  if | fTextual f == TSoftBreak || fTextual f == TLineBreak ->
-                         st { splitChunks = splitChunks st |> S.empty
-                            , splitCurrCol = 0
-                            }
-                     | available >= fsize ->
-                         st { splitChunks  = addFragment f (splitChunks st)
-                            , splitCurrCol = splitCurrCol st + fsize
-                            }
-                     | fTextual f == TSpace ->
-                         st { splitChunks = splitChunks st |> S.empty
-                            , splitCurrCol = 0
-                            }
-                     | otherwise ->
-                         st { splitChunks  = splitChunks st |> S.singleton f
-                            , splitCurrCol = fsize
-                            }
-                available = maxCols - splitCurrCol st
-                fsize = fragmentSize f
-                addFragment x (viewr-> ls :> l) = ( ls |> (l |> x))
-                addFragment _ _ = error "[unreachable]"
-        go st _                 = st
-
-fragmentSize :: Fragment -> Int
-fragmentSize f = case fTextual f of
-  TStr t     -> textWidth t
-  TLink t    -> textWidth t
-  TRawHtml t -> textWidth t
-  TEditSentinel -> textWidth editMarking
-  TEditRecentlySentinel -> textWidth editMarking
-  TSpace     -> 1
-  TLineBreak -> 0
-  TSoftBreak -> 0
-  TComplex fs -> sum $ fragmentSize <$> fs
-
-strOf :: TextFragment -> Text
-strOf f = case f of
-  TStr t     -> t
-  TLink t    -> t
-  TRawHtml t -> t
-  TEditSentinel -> editMarking
-  TEditRecentlySentinel -> editMarking
-  TSpace     -> " "
-  TComplex fs -> T.concat $ F.toList $ (strOf . fTextual) <$> fs
-  _          -> ""
-
--- This finds adjacent string-ey fragments and concats them, so
--- we can use fewer widgets
-gatherWidgets :: Text -> Seq Fragment -> Seq (Widget a)
-gatherWidgets curUser (viewl-> (Fragment frag style :< rs)) = go style (strOf frag) rs
-  where go s t (viewl-> (Fragment f s' :< xs))
-          | s == s' = go s (t <> strOf f) xs
-        go s t xs =
-          let rawText = B.txt (removeCursor t)
-              rawWidget = case s of
-                Normal -> rawText
-                Emph   -> B.withDefAttr clientEmphAttr rawText
-                Edited -> B.withDefAttr editedMarkingAttr $ B.txt t
-                EditedRecently -> B.withDefAttr editedRecentlyMarkingAttr $ B.txt t
-                Strong -> B.withDefAttr clientStrongAttr rawText
-                Code   -> B.withDefAttr codeAttr rawText
-                Link l ->
-                    B.hyperlink l $ B.withDefAttr urlAttr $ case frag of
-                        TComplex fs ->
-                            hBox $ gatherWidgets curUser fs
-                        _ ->
-                            rawText
-                Emoji  -> B.withDefAttr emojiAttr rawText
-                User u -> colorUsername curUser u t
-                Channel -> B.withDefAttr channelNameAttr rawText
-              widget
-                | T.any (== cursorSentinel) t = B.visible rawWidget
-                | otherwise = rawWidget
-          in widget <| gatherWidgets curUser xs
-gatherWidgets _ _ =
-  S.empty
-
-textWithCursor :: Text -> Widget a
-textWithCursor t
-    | T.any (== cursorSentinel) t = B.visible $ B.txt $ removeCursor t
-    | otherwise = B.txt t
-
-findVerbatimChunk :: C.Blocks -> Maybe Text
-findVerbatimChunk = getFirst . F.foldMap go
-  where go (C.CodeBlock _ t) = First (Just t)
-        go _                 = First Nothing
diff --git a/src/State/Autocomplete.hs b/src/State/Autocomplete.hs
--- a/src/State/Autocomplete.hs
+++ b/src/State/Autocomplete.hs
@@ -25,6 +25,7 @@
 import           Network.Mattermost.Types (userId, channelId)
 import qualified Network.Mattermost.Endpoints as MM
 
+import           Constants ( userSigil, normalChannelSigil )
 import {-# SOURCE #-} Command ( commandList, printArgSpec )
 import           State.Common
 import {-# SOURCE #-} State.Editing ( Direction(..), tabComplete )
@@ -159,10 +160,10 @@
                            , MentionChannel
                            ]
                 extras = [ SpecialMention m | m <- specials
-                         , (T.toLower searchString) `T.isInfixOf` specialMentionName m
+                         , (T.toLower searchString) `T.isPrefixOf` specialMentionName m
                          ]
 
-            return $ Just $ setCompletionAlternatives ctx searchString (extras <> alts) ty
+            return $ Just $ setCompletionAlternatives ctx searchString (alts <> extras) ty
 
 doChannelAutoCompletion :: AutocompletionType -> AutocompleteContext -> Text -> MH ()
 doChannelAutoCompletion ty ctx searchString = do
diff --git a/src/State/ChannelSelect.hs b/src/State/ChannelSelect.hs
--- a/src/State/ChannelSelect.hs
+++ b/src/State/ChannelSelect.hs
@@ -17,6 +17,7 @@
 
 import qualified Network.Mattermost.Types as MM
 
+import           Constants ( userSigil, normalChannelSigil )
 import           Types
 import qualified Zipper as Z
 
diff --git a/src/State/Channels.hs b/src/State/Channels.hs
--- a/src/State/Channels.hs
+++ b/src/State/Channels.hs
@@ -10,7 +10,6 @@
   , refreshChannelById
   , applyPreferenceChange
   , leaveChannel
-  , leaveChannelIfPossible
   , leaveCurrentChannel
   , getNextUnreadChannel
   , getNextUnreadUserOrChannel
@@ -48,13 +47,15 @@
   , beginCurrentChannelDeleteConfirm
   , toggleChannelListVisibility
   , showChannelInSidebar
+  , updateChannelNotifyProps
   )
 where
 
 import           Prelude ()
 import           Prelude.MH
 
-import           Brick.Main ( viewportScroll, vScrollToBeginning, invalidateCache, invalidateCacheEntry )
+import           Brick.Main ( getVtyHandle, viewportScroll, vScrollToBeginning
+                            , invalidateCache, invalidateCacheEntry )
 import           Brick.Widgets.Edit ( applyEdit, getEditContents, editContentsL )
 import           Control.Concurrent.Async ( runConcurrently, Concurrently(..) )
 import           Control.Exception ( SomeException, try )
@@ -68,12 +69,14 @@
 import qualified Data.Text as T
 import           Data.Text.Zipper ( textZipper, clearZipper, insertMany, gotoEOL )
 import           Data.Time.Clock ( getCurrentTime )
+import qualified Graphics.Vty as Vty
 import           Lens.Micro.Platform
 
 import qualified Network.Mattermost.Endpoints as MM
 import           Network.Mattermost.Lenses
 import           Network.Mattermost.Types
 
+import           Constants ( normalChannelSigil )
 import           InputHistory
 import           State.Common
 import {-# SOURCE #-} State.Messages ( fetchVisibleIfNeeded )
@@ -102,14 +105,24 @@
     prefs <- use (csResources.crUserPreferences)
     now <- liftIO getCurrentTime
     config <- use (csResources.crConfiguration)
-    csFocus %= Z.updateList (mkChannelZipperList now config cconfig prefs cs us)
 
+    let zl = mkChannelZipperList now config cconfig prefs cs us
+    csFocus %= Z.updateList zl
+
     -- Schedule the current sidebar for user status updates at the end
     -- of this MH action.
     newZ <- use csFocus
     myId <- gets myUserId
     scheduleUserStatusFetches $ myId : userIdsFromZipper newZ
 
+    -- Update the window title based on the unread status of the
+    -- channels.
+    let anyUnread = any channelListGroupHasUnread $ fst <$> zl
+        title = "matterhorn" <> if anyUnread then "(*)" else ""
+
+    vty <- mh getVtyHandle
+    liftIO $ Vty.setWindowTitle vty title
+
     -- If the zipper rebuild caused the current channel to change, such
     -- as when the previously-focused channel was removed, we need to
     -- call fetchVisibleIfNeeded on the newly-focused channel to ensure
@@ -942,9 +955,10 @@
 startLeaveCurrentChannel :: MH ()
 startLeaveCurrentChannel = do
     cInfo <- use (csCurrentChannel.ccInfo)
-    case canLeaveChannel cInfo of
-        True -> setMode LeaveChannelConfirm
-        False -> mhError $ GenericError "The /leave command cannot be used with this channel."
+    case cInfo^.cdType of
+        Direct -> hideDMChannel (cInfo^.cdChannelId)
+        Group -> hideDMChannel (cInfo^.cdChannelId)
+        _ -> setMode LeaveChannelConfirm
 
 deleteCurrentChannel :: MH ()
 deleteCurrentChannel = do
@@ -1061,3 +1075,8 @@
         if chType /= Direct
             then setMode DeleteChannelConfirm
             else mhError $ GenericError "Direct message channels cannot be deleted."
+
+updateChannelNotifyProps :: ChannelId -> ChannelNotifyProps -> MH ()
+updateChannelNotifyProps cId notifyProps = do
+    mh $ invalidateCacheEntry ChannelSidebar
+    csChannel(cId).ccInfo.cdNotifyProps .= notifyProps
diff --git a/src/State/Common.hs b/src/State/Common.hs
--- a/src/State/Common.hs
+++ b/src/State/Common.hs
@@ -53,6 +53,7 @@
 import           State.Async
 import           Types
 import           Types.Common
+import           Types.RichText ( unURL )
 
 
 -- * Client Messages
@@ -287,7 +288,7 @@
                     "https://github.com/matterhorn-chat/matterhorn"
 
 prepareLink :: LinkChoice -> IO [String]
-prepareLink link = return [T.unpack $ link^.linkURL]
+prepareLink link = return [T.unpack $ unURL $ link^.linkURL]
 
 prepareAttachment :: FileId -> Session -> IO [String]
 prepareAttachment fId sess = do
diff --git a/src/State/MessageSelect.hs b/src/State/MessageSelect.hs
--- a/src/State/MessageSelect.hs
+++ b/src/State/MessageSelect.hs
@@ -35,10 +35,10 @@
 import           Network.Mattermost.Types
 
 import           Clipboard ( copyToClipboard )
-import           Markdown ( findVerbatimChunk )
 import           State.Common
 import           State.Messages
 import           Types
+import           Types.RichText ( findVerbatimChunk )
 import           Types.Common
 import           Windows.ViewMessage
 
@@ -148,11 +148,13 @@
         Nothing -> error "BUG: openSelectedMessageURLs: no selected message available"
         Just m -> return m
 
+    remainInSelectMode <- use (csResources.crConfiguration.to configMessageSelectAfterURLOpen)
+
     let urls = msgURLs curMsg
     when (not (null urls)) $ do
         openedAll <- and <$> mapM (openURL . OpenLinkChoice) urls
         case openedAll of
-            True -> setMode Main
+            True -> when (not remainInSelectMode) $ setMode Main
             False ->
                 mhError $ ConfigOptionMissing "urlOpenCommand"
 
diff --git a/src/State/Messages.hs b/src/State/Messages.hs
--- a/src/State/Messages.hs
+++ b/src/State/Messages.hs
@@ -96,7 +96,11 @@
         status <- use csConnectionStatus
         case status of
             Disconnected -> do
-                let m = "Cannot send messages while disconnected."
+                let m = T.concat [ "Cannot send messages while disconnected. Enable logging to "
+                                 , "get disconnection information. If Matterhorn's reconnection "
+                                 , "attempts are failing, use `/reconnect` to attempt to "
+                                 , "reconnect manually."
+                                 ]
                 mhError $ GenericError m
             Connected -> do
                 session <- getSession
diff --git a/src/State/NotifyPrefs.hs b/src/State/NotifyPrefs.hs
new file mode 100644
--- /dev/null
+++ b/src/State/NotifyPrefs.hs
@@ -0,0 +1,87 @@
+{-# LANGUAGE OverloadedStrings #-}
+{-# LANGUAGE RankNTypes #-}
+module State.NotifyPrefs
+    ( enterEditNotifyPrefsMode
+    , exitEditNotifyPrefsMode
+    )
+where
+
+import Prelude ()
+import Prelude.MH
+
+import Types
+
+import Network.Mattermost.Types ( ChannelNotifyProps
+                                , User(..)
+                                , UserNotifyProps(..)
+                                , Type(..)
+                                , channelNotifyPropsMarkUnread
+                                , channelNotifyPropsIgnoreChannelMentions
+                                , WithDefault(..)
+                                , NotifyOption(..)
+                                )
+
+import Brick
+import Brick.Forms
+import Lens.Micro.Platform ( Lens', (.=), lens )
+
+muteLens :: Lens' ChannelNotifyProps Bool
+muteLens = lens (\props -> props^.channelNotifyPropsMarkUnreadL == IsValue NotifyOptionMention)
+           (\props muted -> props { channelNotifyPropsMarkUnread =
+                                          if muted
+                                          then IsValue NotifyOptionMention
+                                          else IsValue NotifyOptionAll
+                                  })
+
+channelMentionLens :: Lens' ChannelNotifyProps Bool
+channelMentionLens = lens (\props -> props^.channelNotifyPropsIgnoreChannelMentionsL == IsValue True)
+                     (\props ignoreChannelMentions ->
+                          props { channelNotifyPropsIgnoreChannelMentions = if ignoreChannelMentions
+                                                                            then IsValue True
+                                                                            else Default
+                                })
+
+notifyOptionName :: NotifyOption -> Text
+notifyOptionName NotifyOptionAll = "All activity"
+notifyOptionName NotifyOptionMention = "Mentions"
+notifyOptionName NotifyOptionNone = "Never"
+
+mkNotifyButtons :: ((WithDefault NotifyOption) -> Name)
+                -> Lens' ChannelNotifyProps (WithDefault NotifyOption)
+                -> NotifyOption
+                -> ChannelNotifyProps
+                -> FormFieldState ChannelNotifyProps e Name
+mkNotifyButtons mkName l globalDefault =
+    let optTuple opt = (IsValue opt, mkName $ IsValue opt, notifyOptionName opt)
+        defaultField = (Default, mkName Default, "Global default (" <> notifyOptionName globalDefault <> ")")
+        nonDefault = optTuple <$> [ NotifyOptionAll
+                                  , NotifyOptionMention
+                                  , NotifyOptionNone
+                                  ]
+    in radioField l (defaultField : nonDefault)
+
+notifyPrefsForm :: UserNotifyProps -> ChannelNotifyProps -> Form ChannelNotifyProps e Name
+notifyPrefsForm globalDefaults =
+    newForm [ checkboxField muteLens MuteToggleField "Mute channel"
+            , (padTop $ Pad 1) @@= checkboxField channelMentionLens ChannelMentionsField "Ignore channel mentions"
+            , radioStyle "Desktop notifications" @@=
+                mkNotifyButtons DesktopNotificationsField channelNotifyPropsDesktopL (userNotifyPropsDesktop globalDefaults)
+            , radioStyle "Push notifications" @@=
+                mkNotifyButtons PushNotificationsField channelNotifyPropsPushL (userNotifyPropsPush globalDefaults)
+            ]
+    where radioStyle label = (padTop $ Pad 1 ) . (str label <=>) . (padLeft $ Pad 1)
+
+enterEditNotifyPrefsMode :: MH ()
+enterEditNotifyPrefsMode = do
+    chanInfo <- use (csCurrentChannel.ccInfo)
+    case chanInfo^.cdType of
+      Direct -> mhError $ GenericError "Cannot open notification preferences for DM channel."
+      _ -> do
+        let props = chanInfo^.cdNotifyProps
+        user <- use csMe
+        csNotifyPrefs .= (Just (notifyPrefsForm (userNotifyProps user) props))
+        setMode EditNotifyPrefs
+
+exitEditNotifyPrefsMode :: MH ()
+exitEditNotifyPrefsMode = do
+    setMode Main
diff --git a/src/State/Setup.hs b/src/State/Setup.hs
--- a/src/State/Setup.hs
+++ b/src/State/Setup.hs
@@ -151,6 +151,7 @@
                  result <- loadCustomizations absPath baseTheme
                  case result of
                      Left e -> do
+                         Vty.shutdown teamSelVty
                          putStrLn $ "Error loading theme customization from " <> show absPath <> ": " <> e
                          exitFailure
                      Right t -> return t
diff --git a/src/State/ThemeListOverlay.hs b/src/State/ThemeListOverlay.hs
new file mode 100644
--- /dev/null
+++ b/src/State/ThemeListOverlay.hs
@@ -0,0 +1,86 @@
+module State.ThemeListOverlay
+  ( enterThemeListMode
+
+  , themeListSelectDown
+  , themeListSelectUp
+  , themeListPageDown
+  , themeListPageUp
+
+  , setTheme
+  )
+where
+
+import           Prelude ()
+import           Prelude.MH
+
+import           Brick ( invalidateCache )
+import           Brick.Themes ( themeToAttrMap )
+import qualified Brick.Widgets.List as L
+import qualified Data.Text as T
+import qualified Data.Vector as Vec
+import           Lens.Micro.Platform ( (.=) )
+
+import           Network.Mattermost.Types
+
+import           State.ListOverlay
+import           Themes
+import           Types
+
+
+-- | Show the user list overlay with the given search scope, and issue a
+-- request to gather the first search results.
+enterThemeListMode :: MH ()
+enterThemeListMode =
+    enterListOverlayMode csThemeListOverlay ThemeListOverlay () setInternalTheme getThemesMatching
+
+-- | Move the selection up in the user list overlay by one user.
+themeListSelectUp :: MH ()
+themeListSelectUp = themeListMove L.listMoveUp
+
+-- | Move the selection down in the user list overlay by one user.
+themeListSelectDown :: MH ()
+themeListSelectDown = themeListMove L.listMoveDown
+
+-- | Move the selection up in the user list overlay by a page of users
+-- (themeListPageSize).
+themeListPageUp :: MH ()
+themeListPageUp = themeListMove (L.listMoveBy (-1 * themeListPageSize))
+
+-- | Move the selection down in the user list overlay by a page of users
+-- (themeListPageSize).
+themeListPageDown :: MH ()
+themeListPageDown = themeListMove (L.listMoveBy themeListPageSize)
+
+-- | Transform the user list results in some way, e.g. by moving the
+-- cursor, and then check to see whether the modification warrants a
+-- prefetch of more search results.
+themeListMove :: (L.List Name InternalTheme -> L.List Name InternalTheme) -> MH ()
+themeListMove = listOverlayMove csThemeListOverlay
+
+-- | The number of users in a "page" for cursor movement purposes.
+themeListPageSize :: Int
+themeListPageSize = 10
+
+getThemesMatching :: ()
+                  -> Session
+                  -> Text
+                  -> IO (Vec.Vector InternalTheme)
+getThemesMatching _ _ searchString = do
+    let matching = filter matches internalThemes
+        search = T.toLower searchString
+        matches t = search `T.isInfixOf` T.toLower (internalThemeName t) ||
+                    search `T.isInfixOf` T.toLower (internalThemeDesc t)
+    return $ Vec.fromList matching
+
+setInternalTheme :: InternalTheme -> MH Bool
+setInternalTheme t = do
+    setTheme $ internalThemeName t
+    return False
+
+setTheme :: Text -> MH ()
+setTheme name =
+    case lookupTheme name of
+        Nothing -> enterThemeListMode
+        Just it -> do
+            mh invalidateCache
+            csResources.crTheme .= (themeToAttrMap $ internalTheme it)
diff --git a/src/State/Themes.hs b/src/State/Themes.hs
deleted file mode 100644
--- a/src/State/Themes.hs
+++ /dev/null
@@ -1,34 +0,0 @@
-module State.Themes
-  (
-    listThemes
-  , setTheme
-  )
-where
-
-import           Prelude ()
-import           Prelude.MH
-
-import           Brick ( invalidateCache )
-import           Brick.Themes ( themeToAttrMap )
-import qualified Data.Text as T
-import           Lens.Micro.Platform ( (.=) )
-
-import           State.Common
-import           Themes
-import           Types
-
-
-listThemes :: MH ()
-listThemes = do
-    let themeList = T.intercalate "\n" $
-                    "Available built-in themes:\n" :
-                    (("* " <>) <$> internalThemeName <$> internalThemes)
-    postInfoMessage themeList
-
-setTheme :: Text -> MH ()
-setTheme name =
-    case lookupTheme name of
-        Nothing -> listThemes
-        Just it -> do
-            mh invalidateCache
-            csResources.crTheme .= (themeToAttrMap $ internalTheme it)
diff --git a/src/State/UserListOverlay.hs b/src/State/UserListOverlay.hs
--- a/src/State/UserListOverlay.hs
+++ b/src/State/UserListOverlay.hs
@@ -18,12 +18,13 @@
 import qualified Data.Sequence as Seq
 import qualified Data.Text as T
 import qualified Data.Vector as Vec
-import           Lens.Micro.Platform ( (.~) )
+import           Lens.Micro.Platform ( (.~), (.=) )
 
 import qualified Network.Mattermost.Endpoints as MM
 import qualified Network.Mattermost.Types.Config as MM
 import           Network.Mattermost.Types
 
+import           State.Async ( doAsyncWith, AsyncPriority(Preempt) )
 import           State.Channels ( createOrFocusDMChannel, addUserToCurrentChannel )
 import           State.ListOverlay
 import           Types
@@ -36,12 +37,17 @@
     cId <- use csCurrentChannelId
     myId <- gets myUserId
     myTId <- gets myTeamId
-    enterUserListMode (ChannelMembers cId myTId)
-      (\u -> case u^.uiId /= myId of
-        True -> createOrFocusDMChannel u Nothing >> return True
-        False -> return False
-      )
+    session <- getSession
 
+    doAsyncWith Preempt $ do
+        stats <- MM.mmGetChannelStatistics cId session
+        return $ Just $ do
+            enterUserListMode (ChannelMembers cId myTId) (Just $ channelStatsMemberCount stats)
+              (\u -> case u^.uiId /= myId of
+                True -> createOrFocusDMChannel u Nothing >> return True
+                False -> return False
+              )
+
 -- | Show the user list overlay for showing users that are not members
 -- of the current channel for the purpose of adding them to the
 -- channel.
@@ -50,7 +56,7 @@
     cId <- use csCurrentChannelId
     myId <- gets myUserId
     myTId <- gets myTeamId
-    enterUserListMode (ChannelNonMembers cId myTId)
+    enterUserListMode (ChannelNonMembers cId myTId) Nothing
       (\u -> case u^.uiId /= myId of
         True -> addUserToCurrentChannel u >> return True
         False -> return False
@@ -66,7 +72,7 @@
     let restrictTeam = case MM.clientConfigRestrictDirectMessage <$> config of
             Just MM.RestrictTeam -> Just myTId
             _ -> Nothing
-    enterUserListMode (AllUsers restrictTeam)
+    enterUserListMode (AllUsers restrictTeam) Nothing
       (\u -> case u^.uiId /= myId of
         True -> createOrFocusDMChannel u Nothing >> return True
         False -> return False
@@ -74,8 +80,9 @@
 
 -- | Show the user list overlay with the given search scope, and issue a
 -- request to gather the first search results.
-enterUserListMode :: UserSearchScope -> (UserInfo -> MH Bool) -> MH ()
-enterUserListMode scope enterHandler =
+enterUserListMode :: UserSearchScope -> Maybe Int -> (UserInfo -> MH Bool) -> MH ()
+enterUserListMode scope resultCount enterHandler = do
+    csUserListOverlay.listOverlayRecordCount .= resultCount
     enterListOverlayMode csUserListOverlay UserListOverlay scope enterHandler getUserSearchResults
 
 userInfoFromPair :: User -> Text -> UserInfo
diff --git a/src/TeamSelect.hs b/src/TeamSelect.hs
--- a/src/TeamSelect.hs
+++ b/src/TeamSelect.hs
@@ -18,7 +18,7 @@
 
 import           Network.Mattermost.Types
 
-import           Markdown
+import           Draw.RichText
 import           Types.Common
 
 
diff --git a/src/Themes.hs b/src/Themes.hs
--- a/src/Themes.hs
+++ b/src/Themes.hs
@@ -52,6 +52,8 @@
 
   -- * Username formatting
   , colorUsername
+  , attrForUsername
+  , usernameColorHashBuckets
   )
 where
 
@@ -66,6 +68,7 @@
                                            , attrMappingsForStyle
                                            , highlightedCodeBlockAttr
                                            )
+import           Brick.Forms ( focusedFormInputAttr )
 import           Data.Hashable ( hash )
 import qualified Data.Map as M
 import qualified Data.Text as T
@@ -73,7 +76,7 @@
 import qualified Skylighting.Styles as Sky
 import           Skylighting.Types ( TokenType(..) )
 
-import           Types ( specialUserMentions )
+import           Types ( InternalTheme(..), specialUserMentions )
 
 
 helpAttr :: AttrName
@@ -199,18 +202,15 @@
 messageSelectStatusAttr :: AttrName
 messageSelectStatusAttr = "messageSelectStatus"
 
-data InternalTheme =
-    InternalTheme { internalThemeName :: Text
-                  , internalTheme     :: Theme
-                  }
-
 lookupTheme :: Text -> Maybe InternalTheme
 lookupTheme n = find ((== n) . internalThemeName) internalThemes
 
 internalThemes :: [InternalTheme]
 internalThemes = validateInternalTheme <$>
     [ darkColorTheme
+    , darkColor256Theme
     , lightColorTheme
+    , lightColor256Theme
     ]
 
 validateInternalTheme :: InternalTheme -> InternalTheme
@@ -230,14 +230,23 @@
 defaultTheme = darkColorTheme
 
 lightColorTheme :: InternalTheme
-lightColorTheme = InternalTheme name theme
+lightColorTheme = InternalTheme name theme desc
     where
-        theme = newTheme def lightAttrs
+        theme = newTheme def $ lightAttrs usernameColors16
         name = "builtin:light"
         def = black `on` white
+        desc = "A color theme for terminal windows with light background colors"
 
-lightAttrs :: [(AttrName, Attr)]
-lightAttrs =
+lightColor256Theme :: InternalTheme
+lightColor256Theme = InternalTheme name theme desc
+    where
+        theme = newTheme def $ lightAttrs usernameColors256
+        name = "builtin:light256"
+        def = black `on` white
+        desc = "Like builtin:light, but with 256-color username colors"
+
+lightAttrs :: [Attr] -> [(AttrName, Attr)]
+lightAttrs usernameColors =
     let sty = Sky.kate
     in [ (timeAttr,                         fg black)
        , (currentUserAttr,                  defAttr `withStyle` bold)
@@ -279,6 +288,7 @@
        , (editedMarkingAttr,                fg yellow)
        , (editedRecentlyMarkingAttr,        black `on` yellow)
        , (tabSelectedAttr,                  black `on` yellow)
+       , (focusedFormInputAttr,             black `on` yellow)
        , (FB.fileBrowserCurrentDirectoryAttr, white `on` blue)
        , (FB.fileBrowserSelectionInfoAttr,  white `on` blue)
        , (FB.fileBrowserDirectoryAttr,      fg blue)
@@ -288,11 +298,11 @@
        , (FB.fileBrowserSymbolicLinkAttr,   fg cyan)
        , (FB.fileBrowserUnixSocketAttr,     fg red)
        ] <>
-       ((\(i, a) -> (usernameAttr i, a)) <$> zip [0..] usernameColors) <>
+       ((\(i, a) -> (usernameAttr i, a)) <$> zip [0..usernameColorHashBuckets-1] (cycle usernameColors)) <>
        (filter skipBaseCodeblockAttr $ attrMappingsForStyle sty)
 
-darkAttrs :: [(AttrName, Attr)]
-darkAttrs =
+darkAttrs :: [Attr] -> [(AttrName, Attr)]
+darkAttrs usernameColors =
   let sty = Sky.espresso
   in [ (timeAttr,                         fg white)
      , (currentUserAttr,                  defAttr `withStyle` bold)
@@ -334,6 +344,7 @@
      , (editedMarkingAttr,                fg yellow)
      , (editedRecentlyMarkingAttr,        black `on` yellow)
      , (tabSelectedAttr,                  black `on` yellow)
+     , (focusedFormInputAttr,             black `on` yellow)
      , (FB.fileBrowserCurrentDirectoryAttr, white `on` blue)
      , (FB.fileBrowserSelectionInfoAttr,  white `on` blue)
      , (FB.fileBrowserDirectoryAttr,      fg blue)
@@ -343,19 +354,28 @@
      , (FB.fileBrowserSymbolicLinkAttr,   fg cyan)
      , (FB.fileBrowserUnixSocketAttr,     fg red)
      ] <>
-     ((\(i, a) -> (usernameAttr i, a)) <$> zip [0..] usernameColors) <>
+     ((\(i, a) -> (usernameAttr i, a)) <$> zip [0..usernameColorHashBuckets-1] (cycle usernameColors)) <>
      (filter skipBaseCodeblockAttr $ attrMappingsForStyle sty)
 
 skipBaseCodeblockAttr :: (AttrName, Attr) -> Bool
 skipBaseCodeblockAttr = ((/= highlightedCodeBlockAttr) . fst)
 
 darkColorTheme :: InternalTheme
-darkColorTheme = InternalTheme name theme
+darkColorTheme = InternalTheme name theme desc
     where
-        theme = newTheme def darkAttrs
+        theme = newTheme def $ darkAttrs usernameColors16
         name = "builtin:dark"
         def = defAttr
+        desc = "A color theme for terminal windows with dark background colors"
 
+darkColor256Theme :: InternalTheme
+darkColor256Theme = InternalTheme name theme desc
+    where
+        theme = newTheme def $ darkAttrs usernameColors256
+        name = "builtin:dark256"
+        def = defAttr
+        desc = "Like builtin:dark, but with 256-color username colors"
+
 usernameAttr :: Int -> AttrName
 usernameAttr i = "username" <> (attrName $ show i)
 
@@ -388,11 +408,7 @@
               -- ^ The text to render
               -> Widget a
 colorUsername current username display =
-    let normalizedUsername = T.toLower username
-        aName = if normalizedUsername `elem` specialUserMentions
-                then clientEmphAttr
-                else usernameAttr h
-        h = hash normalizedUsername `mod` length usernameColors
+    let aName = attrForUsername username
         maybeWithCurrentAttr = if current == username
                                then withAttr currentUserAttr
                                else id
@@ -400,8 +416,33 @@
        maybeWithCurrentAttr $
        txt (display)
 
-usernameColors :: [Attr]
-usernameColors =
+-- | Return the attribute name to use for the specified username.
+-- The input username is expected to be the username only (i.e. no
+-- sigil).
+--
+-- If the input username is a special reserved username such as "all",
+-- the @clientEmphAttr@ attribute name will be returned. Otherwise
+-- a hash-bucket username attribute name will be returned based on
+-- the hash value of the username and the number of hash buckets
+-- (@usernameColorHashBuckets@).
+attrForUsername :: Text
+                -- ^ The username to get an attribute for
+                -> AttrName
+attrForUsername username =
+    let normalizedUsername = T.toLower username
+        aName = if normalizedUsername `elem` specialUserMentions
+                then clientEmphAttr
+                else usernameAttr h
+        h = hash normalizedUsername `mod` usernameColorHashBuckets
+    in aName
+
+-- | The number of hash buckets to use when hashing usernames to choose
+-- their colors.
+usernameColorHashBuckets :: Int
+usernameColorHashBuckets = 50
+
+usernameColors16 :: [Attr]
+usernameColors16 =
     [ fg red
     , fg green
     , fg yellow
@@ -416,6 +457,54 @@
     , fg brightCyan
     ]
 
+usernameColors256 :: [Attr]
+usernameColors256 = mkColor <$> username256ColorChoices
+    where
+        mkColor (r, g, b) = defAttr `withForeColor` rgbColor r g b
+
+username256ColorChoices :: [(Integer, Integer, Integer)]
+username256ColorChoices =
+    [ (255, 0, 86)
+    , (158, 0, 142)
+    , (14, 76, 161)
+    , (255, 229, 2)
+    , (149, 0, 58)
+    , (255, 147, 126)
+    , (164, 36, 0)
+    , (98, 14, 0)
+    , (0, 0, 255)
+    , (106, 130, 108)
+    , (0, 174, 126)
+    , (194, 140, 159)
+    , (0, 143, 156)
+    , (95, 173, 78)
+    , (255, 2, 157)
+    , (255, 116, 163)
+    , (152, 255, 82)
+    , (167, 87, 64)
+    , (254, 137, 0)
+    , (1, 208, 255)
+    , (187, 136, 0)
+    , (117, 68, 177)
+    , (165, 255, 210)
+    , (122, 71, 130)
+    , (0, 71, 84)
+    , (181, 0, 255)
+    , (144, 251, 146)
+    , (189, 211, 147)
+    , (229, 111, 254)
+    , (222, 255, 116)
+    , (0, 255, 120)
+    , (0, 155, 255)
+    , (0, 100, 1)
+    , (0, 118, 255)
+    , (133, 169, 0)
+    , (0, 185, 23)
+    , (120, 130, 49)
+    , (0, 255, 198)
+    , (255, 110, 65)
+    ]
+
 -- Functions for dealing with Skylighting styles
 
 attrNameDescription :: ThemeDocumentation -> AttrName -> Maybe Text
@@ -642,6 +731,9 @@
     , ( listSelectedFocusedAttr
       , "The selected channel"
       )
+    , ( focusedFormInputAttr
+      , "A form input that has focus"
+      )
     , ( FB.fileBrowserAttr
       , "The base file browser attribute"
       )
@@ -676,5 +768,5 @@
       , "Attribute for the username of the user running Matterhorn"
       )
     ] <> [ (usernameAttr i, T.pack $ "Username color " <> show i)
-         | i <- [0..(length usernameColors)-1]
+         | i <- [0..usernameColorHashBuckets-1]
          ]
diff --git a/src/Types.hs b/src/Types.hs
--- a/src/Types.hs
+++ b/src/Types.hs
@@ -58,9 +58,13 @@
   , RequestChan
   , UserFetch(..)
   , writeBChan
+  , InternalTheme(..)
 
+  , attrNameToConfig
+
   , mkChannelZipperList
   , ChannelListGroup(..)
+  , channelListGroupHasUnread
 
   , trimChannelSigil
 
@@ -81,6 +85,7 @@
   , csPostMap
   , csRecentChannel
   , csReturnChannel
+  , csThemeListOverlay
   , csPostListOverlay
   , csUserListOverlay
   , csChannelListOverlay
@@ -96,6 +101,8 @@
   , csClientConfig
   , csPendingChannelChange
   , csViewedMessage
+  , csNotifyPrefs
+  , csMe
   , timeZone
   , whenMode
   , setMode
@@ -146,6 +153,7 @@
   , listOverlayEnterHandler
   , listOverlayNewList
   , listOverlayFetchResults
+  , listOverlayRecordCount
 
   , getUsers
 
@@ -252,8 +260,6 @@
   , getNewMessageCutoff
   , getEditedMessageCutoff
 
-  , normalChannelSigil
-
   , HighlightSet(..)
   , UserSet
   , ChannelSet
@@ -272,9 +278,11 @@
 import qualified Graphics.Vty as Vty
 import qualified Brick
 import           Brick ( EventM, Next, Widget )
+import           Brick.Themes ( Theme )
 import           Brick.Main ( invalidateCache, invalidateCacheEntry )
 import           Brick.AttrMap ( AttrMap )
 import qualified Brick.BChan as BCH
+import           Brick.Forms (Form)
 import           Brick.Widgets.Edit ( Editor, editor )
 import           Brick.Widgets.List ( List, list )
 import qualified Brick.Widgets.FileBrowser as FB
@@ -288,6 +296,7 @@
 import qualified Data.Set as Set
 import qualified Data.ByteString as BS
 import qualified Data.Foldable as F
+import qualified Data.Kind as K
 import           Data.Ord ( comparing )
 import qualified Data.HashMap.Strict as HM
 import           Data.List ( sortBy, nub, elemIndex )
@@ -314,6 +323,7 @@
 import           Network.Mattermost.Types.Config
 import           Network.Mattermost.WebSocket ( WebsocketEvent, WebsocketActionResponse )
 
+import           Constants ( userSigil, normalChannelSigil )
 import           InputHistory
 import           Emoji
 import           Types.Common
@@ -341,13 +351,19 @@
     | TokenCommand Text
     deriving (Eq, Read, Show)
 
--- | The type of channel list group headings.
+-- | The type of channel list group headings. Booleans indicate whether
+-- any channels in the group have unread activity.
 data ChannelListGroup =
-    ChannelGroupPublicChannels
-    | ChannelGroupPrivateChannels
-    | ChannelGroupDirectMessages
+    ChannelGroupPublicChannels Bool
+    | ChannelGroupPrivateChannels Bool
+    | ChannelGroupDirectMessages Bool
     deriving (Eq)
 
+channelListGroupHasUnread :: ChannelListGroup -> Bool
+channelListGroupHasUnread (ChannelGroupPublicChannels u) = u
+channelListGroupHasUnread (ChannelGroupPrivateChannels u) = u
+channelListGroupHasUnread (ChannelGroupDirectMessages u) = u
+
 -- | The type of channel list entries.
 data ChannelListEntry =
     CLChannel ChannelId
@@ -438,6 +454,9 @@
            -- ^ The CPU usage policy for the application.
            , configDefaultAttachmentPath :: Maybe FilePath
            -- ^ The default path for browsing attachments
+           , configMessageSelectAfterURLOpen :: Bool
+           -- ^ Whether to remain in message selection mode after
+           -- opening URL(s)
            } deriving (Eq, Show)
 
 -- | The policy for CPU usage.
@@ -481,8 +500,10 @@
 hasUnread' chan = fromMaybe False $ do
     let info = _ccInfo chan
     lastViewTime <- _cdViewed info
-    return $ ((_cdUpdated info) > lastViewTime) ||
-             (isJust $ _cdEditedMessageThreshold info)
+    return $ _cdMentionCount info > 0 ||
+             (not (isMuted chan) &&
+              ((_cdUpdated info) > lastViewTime) ||
+              (isJust $ _cdEditedMessageThreshold info))
 
 mkChannelZipperList :: UTCTime
                     -> Config
@@ -492,28 +513,32 @@
                     -> Users
                     -> [(ChannelListGroup, [ChannelListEntry])]
 mkChannelZipperList now config cconfig prefs cs us =
-    [ (ChannelGroupPublicChannels, getChannelIdsInOrder cs Ordinary)
-    , (ChannelGroupPrivateChannels, getChannelIdsInOrder cs Private)
-    , (ChannelGroupDirectMessages, getDMChannelsInOrder now config cconfig prefs us cs)
+    [ let (anyUnread, entries) = getChannelEntriesInOrder cs Ordinary
+      in (ChannelGroupPublicChannels anyUnread, entries)
+    , let (anyUnread, entries) = getChannelEntriesInOrder cs Private
+      in (ChannelGroupPrivateChannels anyUnread, entries)
+    , (ChannelGroupDirectMessages False, getDMChannelEntriesInOrder now config cconfig prefs us cs)
     ]
 
-getChannelIdsInOrder :: ClientChannels -> Type -> [ChannelListEntry]
-getChannelIdsInOrder cs ty =
+getChannelEntriesInOrder :: ClientChannels -> Type -> (Bool, [ChannelListEntry])
+getChannelEntriesInOrder cs ty =
     let matches (_, info) = info^.ccInfo.cdType == ty
-    in fmap (CLChannel . fst) $
-       sortBy (comparing ((^.ccInfo.cdDisplayName.to T.toLower) . snd)) $
-       filteredChannels matches cs
+        pairs = filteredChannels matches cs
+        anyUnread = or $ (hasUnread' . snd) <$> pairs
+        entries = fmap (CLChannel . fst) $
+                  sortBy (comparing ((^.ccInfo.cdDisplayName.to T.toLower) . snd)) pairs
+    in (anyUnread, entries)
 
-getDMChannelsInOrder :: UTCTime
-                     -> Config
-                     -> Maybe ClientConfig
-                     -> UserPreferences
-                     -> Users
-                     -> ClientChannels
-                     -> [ChannelListEntry]
-getDMChannelsInOrder now config cconfig prefs us cs =
-    let oneOnOneDmChans = getDMChannels now config cconfig prefs us cs
-        groupChans = getGroupDMChannels now config prefs cs
+getDMChannelEntriesInOrder :: UTCTime
+                           -> Config
+                           -> Maybe ClientConfig
+                           -> UserPreferences
+                           -> Users
+                           -> ClientChannels
+                           -> [ChannelListEntry]
+getDMChannelEntriesInOrder now config cconfig prefs us cs =
+    let oneOnOneDmChans = getDMChannelEntries now config cconfig prefs us cs
+        groupChans = getGroupDMChannelEntries now config prefs cs
         allDmChans = groupChans <> oneOnOneDmChans
         sorter (u1, n1, _) (u2, n2, _) =
             if u1 == u2
@@ -541,25 +566,25 @@
     | otherwise =
         u^.uiName
 
-getGroupDMChannels :: UTCTime
-                   -> Config
-                   -> UserPreferences
-                   -> ClientChannels
-                   -> [(Bool, T.Text, ChannelListEntry)]
-getGroupDMChannels now config prefs cs =
+getGroupDMChannelEntries :: UTCTime
+                         -> Config
+                         -> UserPreferences
+                         -> ClientChannels
+                         -> [(Bool, T.Text, ChannelListEntry)]
+getGroupDMChannelEntries now config prefs cs =
     let matches (_, info) = info^.ccInfo.cdType == Group &&
                             groupChannelShouldAppear now config prefs info
     in fmap (\(cId, ch) -> (hasUnread' ch, ch^.ccInfo.cdDisplayName, CLGroupDM cId)) $
        filteredChannels matches cs
 
-getDMChannels :: UTCTime
-              -> Config
-              -> Maybe ClientConfig
-              -> UserPreferences
-              -> Users
-              -> ClientChannels
-              -> [(Bool, T.Text, ChannelListEntry)]
-getDMChannels now config cconfig prefs us cs =
+getDMChannelEntries :: UTCTime
+                    -> Config
+                    -> Maybe ClientConfig
+                    -> UserPreferences
+                    -> Users
+                    -> ClientChannels
+                    -> [(Bool, T.Text, ChannelListEntry)]
+getDMChannelEntries now config cconfig prefs us cs =
     let mapping = allDmChannelMappings cs
         mappingWithUserInfo = catMaybes $ getInfo <$> mapping
         getInfo (uId, cId) = do
@@ -637,9 +662,11 @@
     | JoinChannelList
     | UrlList
     | MessagePreviewViewport
+    | ThemeListSearchInput
     | UserListSearchInput
     | JoinChannelListSearchInput
     | UserListSearchResults
+    | ThemeListSearchResults
     | ViewMessageArea
     | ViewMessageReactionsArea
     | ChannelSidebar
@@ -650,6 +677,10 @@
     | ReactionEmojiList
     | ReactionEmojiListInput
     | TabbedWindowTabBar
+    | MuteToggleField
+    | ChannelMentionsField
+    | DesktopNotificationsField (WithDefault NotifyOption)
+    | PushNotificationsField (WithDefault NotifyOption)
     deriving (Eq, Show, Ord)
 
 -- | The sum type of exceptions we expect to encounter on authentication
@@ -689,27 +720,23 @@
     | CLId Int
     deriving (Eq, Show)
 
--- Sigils
-normalChannelSigil :: Text
-normalChannelSigil = "~"
-
 -- ** Channel-matching types
 
 -- | A match in channel selection mode.
 data ChannelSelectMatch =
-    ChannelSelectMatch { nameBefore     :: Text
+    ChannelSelectMatch { nameBefore :: Text
                        -- ^ The content of the match before the user's
                        -- matching input.
-                       , nameMatched    :: Text
+                       , nameMatched :: Text
                        -- ^ The potion of the name that matched the
                        -- user's input.
-                       , nameAfter      :: Text
+                       , nameAfter :: Text
                        -- ^ The portion of the name that came after the
                        -- user's matching input.
-                       , matchFull      :: Text
+                       , matchFull :: Text
                        -- ^ The full string for this entry so it doesn't
                        -- have to be reassembled from the parts above.
-                       , matchEntry     :: ChannelListEntry
+                       , matchEntry :: ChannelListEntry
                        -- ^ The original entry data corresponding to the
                        -- text match.
                        }
@@ -1061,9 +1088,11 @@
     | UserListOverlay
     | ReactionEmojiListOverlay
     | ChannelListOverlay
+    | ThemeListOverlay
     | ViewMessage
     | ManageAttachments
     | ManageAttachmentsBrowseFiles
+    | EditNotifyPrefs
     deriving (Eq)
 
 -- | We're either connected or we're not.
@@ -1292,6 +1321,8 @@
               -- queue length if so.
               , _csMessageSelect :: MessageSelectState
               -- ^ The state of message selection mode.
+              , _csThemeListOverlay :: ListOverlayState InternalTheme ()
+              -- ^ The state of the theme list overlay.
               , _csPostListOverlay :: PostListOverlayState
               -- ^ The state of the post list overlay.
               , _csUserListOverlay :: ListOverlayState UserInfo UserSearchScope
@@ -1318,6 +1349,11 @@
               -- consult the chat state for the latest *version* of any
               -- message with an ID here, to be sure that the latest
               -- version is used (e.g. if it gets edited, etc.).
+              , _csNotifyPrefs :: Maybe (Form ChannelNotifyProps MHEvent Name)
+              -- ^ A form for editing the notification preferences for
+              -- the current channel. This is set when entering
+              -- EditNotifyPrefs mode and updated when the user
+              -- changes the form state.
               }
 
 -- | Handles for the View Message window's tabs.
@@ -1367,6 +1403,7 @@
                      , _csConnectionStatus            = Connected
                      , _csWorkerIsBusy                = Nothing
                      , _csMessageSelect               = MessageSelectState Nothing
+                     , _csThemeListOverlay            = nullThemeListOverlayState
                      , _csPostListOverlay             = PostListOverlayState emptyDirSeq Nothing
                      , _csUserListOverlay             = nullUserListOverlayState
                      , _csChannelListOverlay          = nullChannelListOverlayState
@@ -1374,6 +1411,7 @@
                      , _csClientConfig                = Nothing
                      , _csPendingChannelChange        = Nothing
                      , _csViewedMessage               = Nothing
+                     , _csNotifyPrefs                 = Nothing
                      }
 
 nullChannelListOverlayState :: ListOverlayState Channel ChannelSearchScope
@@ -1386,8 +1424,22 @@
                         , _listOverlayEnterHandler   = const $ return False
                         , _listOverlayNewList        = newList
                         , _listOverlayFetchResults   = const $ const $ const $ return mempty
+                        , _listOverlayRecordCount    = Nothing
                         }
 
+nullThemeListOverlayState :: ListOverlayState InternalTheme ()
+nullThemeListOverlayState =
+    let newList rs = list ThemeListSearchResults rs 3
+    in ListOverlayState { _listOverlaySearchResults  = newList mempty
+                        , _listOverlaySearchInput    = editor ThemeListSearchInput (Just 1) ""
+                        , _listOverlaySearchScope    = ()
+                        , _listOverlaySearching      = False
+                        , _listOverlayEnterHandler   = const $ return False
+                        , _listOverlayNewList        = newList
+                        , _listOverlayFetchResults   = const $ const $ const $ return mempty
+                        , _listOverlayRecordCount    = Nothing
+                        }
+
 nullUserListOverlayState :: ListOverlayState UserInfo UserSearchScope
 nullUserListOverlayState =
     let newList rs = list UserListSearchResults rs 1
@@ -1398,6 +1450,7 @@
                         , _listOverlayEnterHandler   = const $ return False
                         , _listOverlayNewList        = newList
                         , _listOverlayFetchResults   = const $ const $ const $ return mempty
+                        , _listOverlayRecordCount    = Nothing
                         }
 
 nullEmojiListOverlayState :: ListOverlayState (Bool, T.Text) ()
@@ -1410,6 +1463,7 @@
                         , _listOverlayEnterHandler   = const $ return False
                         , _listOverlayNewList        = newList
                         , _listOverlayFetchResults   = const $ const $ const $ return mempty
+                        , _listOverlayRecordCount    = Nothing
                         }
 
 -- | The state of channel selection mode.
@@ -1435,6 +1489,12 @@
                          , _postListSelected :: Maybe PostId
                          }
 
+data InternalTheme =
+    InternalTheme { internalThemeName :: Text
+                  , internalTheme :: Theme
+                  , internalThemeDesc :: Text
+                  }
+
 -- | The state of the search result list overlay. Type 'a' is the type
 -- of data in the list. Type 'b' is the search scope type.
 data ListOverlayState a b =
@@ -1458,6 +1518,8 @@
                      , _listOverlayFetchResults :: b -> Session -> Text -> IO (Vec.Vector a)
                      -- ^ The function to call to issue a search query
                      -- to the server.
+                     , _listOverlayRecordCount :: Maybe Int
+                     -- ^ The total number of available records, if known.
                      }
 
 -- | The scope for searching for users in a user list overlay.
@@ -1882,7 +1944,7 @@
 
 -- | The 'CmdArgs' type represents the arguments to a slash-command; the
 -- type parameter represents the argument structure.
-data CmdArgs :: * -> * where
+data CmdArgs :: K.Type -> K.Type where
     NoArg    :: CmdArgs ()
     LineArg  :: Text -> CmdArgs Text
     UserArg  :: CmdArgs rest -> CmdArgs (Text, rest)
@@ -1973,6 +2035,9 @@
                  , hChannelSet = getChannelNameSet $ st^.csChannels
                  , hSyntaxMap = st^.csResources.crSyntaxMap
                  }
+
+attrNameToConfig :: Brick.AttrName -> Text
+attrNameToConfig = T.pack . intercalate "." . Brick.attrNameComponents
 
 -- From: https://docs.mattermost.com/help/messaging/mentioning-teammates.html
 specialUserMentions :: [T.Text]
diff --git a/src/Types/Channels.hs b/src/Types/Channels.hs
--- a/src/Types/Channels.hs
+++ b/src/Types/Channels.hs
@@ -20,7 +20,7 @@
   , cdViewed, cdNewMessageIndicator, cdEditedMessageThreshold, cdUpdated
   , cdName, cdDisplayName, cdHeader, cdPurpose, cdType
   , cdMentionCount, cdTypingUsers, cdDMUserId, cdChannelId
-  , cdSidebarShowOverride
+  , cdSidebarShowOverride, cdNotifyProps
   -- * Lenses created for accessing ChannelContents fields
   , cdMessages, cdFetchPending
   -- * Creating ClientChannel objects
@@ -41,6 +41,11 @@
   , addChannelTypingUser
   -- * Notification settings
   , notifyPreference
+  , isMuted
+  , channelNotifyPropsMarkUnreadL
+  , channelNotifyPropsIgnoreChannelMentionsL
+  , channelNotifyPropsDesktopL
+  , channelNotifyPropsPushL
   -- * Miscellaneous channel-related operations
   , canLeaveChannel
   , preferredChannelName
@@ -240,11 +245,16 @@
 makeLenses ''ClientChannel
 makeLenses ''EphemeralEditState
 
+isMuted :: ClientChannel -> Bool
+isMuted cc = cc^.ccInfo.cdNotifyProps.channelNotifyPropsMarkUnreadL ==
+             IsValue NotifyOptionMention
+
 notifyPreference :: User -> ClientChannel -> NotifyOption
 notifyPreference u cc =
-    case cc^.ccInfo.cdNotifyProps.channelNotifyPropsDesktopL of
-        IsValue v -> v
-        Default   -> (userNotifyProps u)^.userNotifyPropsDesktopL
+    if isMuted cc then NotifyOptionNone
+    else case cc^.ccInfo.cdNotifyProps.channelNotifyPropsDesktopL of
+             IsValue v -> v
+             Default   -> (userNotifyProps u)^.userNotifyPropsDesktopL
 
 -- ** Miscellaneous channel operations
 
diff --git a/src/Types/KeyEvents.hs b/src/Types/KeyEvents.hs
--- a/src/Types/KeyEvents.hs
+++ b/src/Types/KeyEvents.hs
@@ -88,8 +88,11 @@
   | ScrollRightEvent
   | PageUpEvent
   | PageDownEvent
+  | PageRightEvent
+  | PageLeftEvent
   | ScrollTopEvent
   | ScrollBottomEvent
+  | SelectOldestMessageEvent
 
   -- select events---not the same as scrolling sometimes!
   | SelectUpEvent
@@ -118,6 +121,9 @@
   | AttachmentListAddEvent
   | AttachmentListDeleteEvent
   | AttachmentOpenEvent
+
+  -- Form submission
+  | FormSubmitEvent
     deriving (Eq, Show, Ord, Enum)
 
 allEvents :: [KeyEvent]
@@ -176,8 +182,11 @@
   , ScrollRightEvent
   , PageUpEvent
   , PageDownEvent
+  , PageLeftEvent
+  , PageRightEvent
   , ScrollTopEvent
   , ScrollBottomEvent
+  , SelectOldestMessageEvent
 
   , SelectUpEvent
   , SelectDownEvent
@@ -200,6 +209,7 @@
   , AttachmentListAddEvent
   , AttachmentListDeleteEvent
   , AttachmentOpenEvent
+  , FormSubmitEvent
   ]
 
 eventToBinding :: Vty.Event -> Binding
@@ -392,8 +402,11 @@
   ScrollRightEvent  -> "scroll-right"
   PageUpEvent       -> "page-up"
   PageDownEvent     -> "page-down"
+  PageLeftEvent     -> "page-left"
+  PageRightEvent    -> "page-right"
   ScrollTopEvent    -> "scroll-top"
   ScrollBottomEvent -> "scroll-bottom"
+  SelectOldestMessageEvent -> "select-oldest-message"
 
   SelectUpEvent   -> "select-up"
   SelectDownEvent -> "select-down"
@@ -417,3 +430,5 @@
   AttachmentListAddEvent    -> "add-to-attachment-list"
   AttachmentListDeleteEvent -> "delete-from-attachment-list"
   AttachmentOpenEvent       -> "open-attachment"
+
+  FormSubmitEvent -> "submit-form"
diff --git a/src/Types/Messages.hs b/src/Types/Messages.hs
--- a/src/Types/Messages.hs
+++ b/src/Types/Messages.hs
@@ -94,13 +94,12 @@
   , removeMatchesFromSubset
   , withFirstMessage
   , msgURLs
-  , altInlinesString
 
   , LinkChoice(LinkChoice)
   , linkUser
   , linkURL
   , linkTime
-  , linkName
+  , linkLabel
   , linkFileId
   )
 where
@@ -108,8 +107,6 @@
 import           Prelude ()
 import           Prelude.MH
 
-import           Cheapskate ( Blocks )
-import qualified Cheapskate as C
 import           Control.Monad
 import qualified Data.Foldable as F
 import           Data.Hashable ( Hashable )
@@ -126,7 +123,10 @@
 
 import           Types.DirectionalSeq
 import           Types.Posts
-import           Types.UserNames
+import           Types.RichText ( RichTextBlock(..), Element(..)
+                                , ElementData(..), findUsernames, blockGetURLs
+                                , ElementStyle(..), URL(..), parseMarkdown
+                                )
 
 
 -- | The state of a message's thread context.
@@ -155,7 +155,7 @@
 -- | A 'Message' is any message we might want to render, either from
 --   Mattermost itself or from a client-internal source.
 data Message = Message
-  { _mText          :: Blocks
+  { _mText          :: Seq RichTextBlock
   , _mMarkdownSource :: Text
   , _mUser          :: UserRef
   , _mDate          :: ServerTime
@@ -286,8 +286,8 @@
 data LinkChoice =
     LinkChoice { _linkTime   :: ServerTime
                , _linkUser   :: UserRef
-               , _linkName   :: Text
-               , _linkURL    :: Text
+               , _linkLabel  :: Maybe (Seq Element)
+               , _linkURL    :: URL
                , _linkFileId :: Maybe FileId
                } deriving (Eq, Show)
 
@@ -299,7 +299,7 @@
 -- associated with passing a link to the local browser.
 clientMessageToMessage :: ClientMessage -> Message
 clientMessageToMessage cm = Message
-  { _mText          = getBlocks (cm^.cmText)
+  { _mText          = parseMarkdown (cm^.cmText)
   , _mMarkdownSource = cm^.cmText
   , _mUser          = NoUser
   , _mDate          = cm^.cmDate
@@ -361,7 +361,7 @@
 
 newMessageOfType :: Text -> MessageType -> ServerTime -> Message
 newMessageOfType text typ d = Message
-  { _mText         = getBlocks text
+  { _mText         = parseMarkdown text
   , _mMarkdownSource = text
   , _mUser         = NoUser
   , _mDate         = d
@@ -719,51 +719,21 @@
 withFirstMessage = withDirSeqHead
 
 msgURLs :: Message -> Seq LinkChoice
-msgURLs msg
-  | NoUser <- msg^.mUser = mempty
-  | otherwise =
-  let uid = msg^.mUser
-      msgUrls = (\ (url, text) -> LinkChoice (msg^.mDate) uid text url Nothing) <$>
-                  (mconcat $ blockGetURLs <$> (toList $ msg^.mText))
+msgURLs msg =
+  let uRef = msg^.mUser
+      msgUrls = (\ (url, text) -> LinkChoice (msg^.mDate) uRef text url Nothing) <$>
+                  (Seq.fromList $ mconcat $ blockGetURLs <$> (toList $ msg^.mText))
       attachmentURLs = (\ a ->
                           LinkChoice
                             (msg^.mDate)
-                            uid
-                            ("attachment `" <> (a^.attachmentName) <> "`")
-                            (a^.attachmentURL)
+                            uRef
+                            (Just $ attachmentLabel a)
+                            (URL $ a^.attachmentURL)
                             (Just (a^.attachmentFileId)))
                        <$> (msg^.mAttachments)
+      attachmentLabel a =
+          Seq.fromList [ Element Normal $ EText "attachment"
+                       , Element Normal ESpace
+                       , Element Code $ EText $ a^.attachmentName
+                       ]
   in msgUrls <> attachmentURLs
-
-blockGetURLs :: C.Block -> Seq.Seq (Text, Text)
-blockGetURLs (C.Para is) = mconcat $ inlineGetURLs <$> toList is
-blockGetURLs (C.Header _ is) = mconcat $ inlineGetURLs <$> toList is
-blockGetURLs (C.Blockquote bs) = mconcat $ blockGetURLs <$> toList bs
-blockGetURLs (C.List _ _ bss) = mconcat $ mconcat $ (blockGetURLs <$>) <$> (toList <$> bss)
-blockGetURLs _ = mempty
-
-inlineGetURLs :: C.Inline -> Seq.Seq (Text, Text)
-inlineGetURLs (C.Emph is) = mconcat $ inlineGetURLs <$> toList is
-inlineGetURLs (C.Strong is) = mconcat $ inlineGetURLs <$> toList is
-inlineGetURLs (C.Link is url "") = (url, inlinesText is) Seq.<| (mconcat $ inlineGetURLs <$> toList is)
-inlineGetURLs (C.Link is _ url) = (url, inlinesText is) Seq.<| (mconcat $ inlineGetURLs <$> toList is)
-inlineGetURLs (C.Image is url _) = Seq.singleton (url, inlinesText is)
-inlineGetURLs _ = mempty
-
-inlinesText :: Seq C.Inline -> Text
-inlinesText = F.fold . fmap go
-  where go (C.Str t)       = t
-        go C.Space         = " "
-        go C.SoftBreak     = " "
-        go C.LineBreak     = " "
-        go (C.Emph is)     = F.fold (fmap go is)
-        go (C.Strong is)   = F.fold (fmap go is)
-        go (C.Code t)      = t
-        go (C.Link is _ _) = F.fold (fmap go is)
-        go (C.Image is _ _) = "[image" <> altInlinesString is <> "]"
-        go (C.Entity t)    = t
-        go (C.RawHtml t)   = t
-
-altInlinesString :: Seq C.Inline -> Text
-altInlinesString is | Seq.null is = ""
-                    | otherwise = ":" <> inlinesText is
diff --git a/src/Types/Posts.hs b/src/Types/Posts.hs
--- a/src/Types/Posts.hs
+++ b/src/Types/Posts.hs
@@ -42,16 +42,12 @@
   , postIsJoin
   , postIsTopicChange
   , postIsEmote
-
-  , getBlocks
   )
 where
 
 import           Prelude ()
 import           Prelude.MH
 
-import           Cheapskate ( Blocks )
-import qualified Cheapskate as C
 import qualified Data.Map.Strict as Map
 import qualified Data.Sequence as Seq
 import qualified Data.Text as T
@@ -63,6 +59,7 @@
 import           Network.Mattermost.Types
 
 import           Types.Common
+import           Types.RichText ( RichTextBlock(Blockquote), parseMarkdown )
 
 
 -- * Client Messages
@@ -113,7 +110,7 @@
 --   the Mattermost 'Post' type, with unnecessary information
 --   removed and some preprocessing done.
 data ClientPost = ClientPost
-  { _cpText          :: Blocks
+  { _cpText          :: Seq RichTextBlock
   , _cpMarkdownSource :: Text
   , _cpUser          :: Maybe UserId
   , _cpUserOverride  :: Maybe Text
@@ -154,10 +151,6 @@
 
 -- ** Creating 'ClientPost' Values
 
--- | Parse text as Markdown and extract the AST
-getBlocks :: Text -> Blocks
-getBlocks s = bs where C.Doc _ bs = C.markdown C.def s
-
 -- | Determine the internal 'PostType' based on a 'Post'
 postClientPostType :: Post -> ClientPostType
 postClientPostType cp =
@@ -201,7 +194,7 @@
 toClientPost :: Post -> Maybe PostId -> ClientPost
 toClientPost p parentId =
   let src = unEmote (postClientPostType p) $ sanitizeUserText $ postMessage p
-  in ClientPost { _cpText          = getBlocks src <> getAttachmentText p
+  in ClientPost { _cpText          = parseMarkdown src <> getAttachmentText p
                 , _cpMarkdownSource = src
                 , _cpUser          = postUserId p
                 , _cpUserOverride  = p^.postPropsL.postPropsOverrideUsernameL
@@ -221,13 +214,13 @@
 
 -- | Right now, instead of treating 'attachment' properties specially, we're
 --   just going to roll them directly into the message text
-getAttachmentText :: Post -> Blocks
+getAttachmentText :: Post -> Seq RichTextBlock
 getAttachmentText p =
   case p^.postPropsL.postPropsAttachmentsL of
     Nothing -> Seq.empty
     Just attachments ->
-      fmap (C.Blockquote . render) attachments
-  where render att = getBlocks (att^.ppaTextL) <> getBlocks (att^.ppaFallbackL)
+      fmap (Blockquote . render) attachments
+  where render att = parseMarkdown (att^.ppaTextL) <> parseMarkdown (att^.ppaFallbackL)
 
 -- ** 'ClientPost' Lenses
 
diff --git a/src/Types/RichText.hs b/src/Types/RichText.hs
new file mode 100644
--- /dev/null
+++ b/src/Types/RichText.hs
@@ -0,0 +1,390 @@
+-- | This module provides a set of data types to represent message text.
+-- The types here are based loosely on the @cheapskate@ package's types
+-- but provide higher-level support for the kinds of things we find in
+-- Mattermost messages such as user and channel references.
+--
+-- To parse a Markdown document, use 'parseMarkdown'. To actually render
+-- text in this representation, see the module 'Draw.RichText'.
+module Types.RichText
+  ( RichTextBlock(..)
+  , ListType(..)
+  , CodeBlockInfo(..)
+  , NumDecoration(..)
+  , Element(..)
+  , ElementData(..)
+  , ElementStyle(..)
+
+  , URL(..)
+  , unURL
+
+  , parseMarkdown
+  , setElementStyle
+
+  , findUsernames
+  , blockGetURLs
+  , findVerbatimChunk
+
+  -- Exposed for testing only:
+  , fromMarkdownBlocks
+  )
+where
+
+import           Prelude ()
+import           Prelude.MH
+
+import qualified Cheapskate as C
+import           Data.Char ( isAlphaNum, isAlpha )
+import qualified Data.Foldable as F
+import           Data.Monoid (First(..))
+import qualified Data.Set as S
+import qualified Data.Sequence as Seq
+import           Data.Sequence ( (<|), ViewL((:<)) )
+import qualified Data.Text as T
+
+import           Constants ( userSigil, normalChannelSigil )
+
+-- | A block in a rich text document.
+data RichTextBlock =
+    Para (Seq Element)
+    -- ^ A paragraph.
+    | Header Int (Seq Element)
+    -- ^ A section header with specified depth and contents.
+    | Blockquote (Seq RichTextBlock)
+    -- ^ A blockquote.
+    | List Bool ListType (Seq (Seq RichTextBlock))
+    -- ^ An itemized list.
+    | CodeBlock CodeBlockInfo Text
+    -- ^ A code block.
+    | HTMLBlock Text
+    -- ^ A fragment of raw HTML.
+    | HRule
+    -- ^ A horizontal rule.
+    deriving (Show)
+
+-- | The type of itemized list items.
+data ListType =
+    Bullet Char
+    -- ^ Decorate the items with bullet using the specified character.
+    | Numbered NumDecoration Int
+    -- ^ Number the items starting at the specified number; use the
+    -- indicated decoration following the number.
+    deriving (Eq, Show)
+
+-- | Information about a code block.
+data CodeBlockInfo =
+    CodeBlockInfo { codeBlockLanguage :: Maybe Text
+                  -- ^ The language of the source code in the code
+                  -- block, if any. This is encoded in Markdown as a
+                  -- sequence of non-whitespace characters following the
+                  -- fenced code block opening backticks.
+                  , codeBlockInfo :: Maybe Text
+                  -- ^ Any text that comes after the language token.
+                  -- This text is separated from the language token by
+                  -- whitespace.
+                  }
+                  deriving (Eq, Show)
+
+-- | Ways to decorate numbered itemized list items. The decoration
+-- follows the list item number.
+data NumDecoration =
+    Paren
+    | Period
+    deriving (Eq, Show)
+
+-- | A single logical inline element in a rich text block.
+data Element =
+    Element { eStyle :: ElementStyle
+            -- ^ The element's visual style.
+            , eData :: ElementData
+            -- ^ The element's data.
+            }
+            deriving (Show, Eq)
+
+setElementStyle :: ElementStyle -> Element -> Element
+setElementStyle s e = e { eStyle = s }
+
+-- | A URL.
+newtype URL = URL Text
+            deriving (Eq, Show, Ord)
+
+unURL :: URL -> Text
+unURL (URL url) = url
+
+-- | The kinds of data that can appear in rich text elements.
+data ElementData =
+    EText Text
+    -- ^ A sequence of non-whitespace characters.
+    | ESpace
+    -- ^ A single space.
+    | ESoftBreak
+    -- ^ A soft line break.
+    | ELineBreak
+    -- ^ A hard line break.
+    | ERawHtml Text
+    -- ^ Raw HTML.
+    | EEditSentinel Bool
+    -- ^ A sentinel indicating that some text has been edited (used
+    -- to indicate that mattermost messages have been edited by their
+    -- authors). This has no parsable representation; it is only used
+    -- to annotate a message prior to rendering to add a visual editing
+    -- indicator. The boolean indicates whether the edit was "recent"
+    -- (True) or not (False).
+    | EUser Text
+    -- ^ A user reference. The text here includes only the username, not
+    -- the sigil.
+    | EChannel Text
+    -- ^ A channel reference. The text here includes only the channel
+    -- name, not the sigil.
+    | EHyperlink URL (Maybe (Seq Element))
+    -- ^ A hyperlink to the specified URL. Optionally provides an
+    -- element sequence indicating the URL's text label; if absent, the
+    -- label is understood to be the URL itself.
+    | EImage URL (Maybe (Seq Element))
+    -- ^ An image at the specified URL. Optionally provides an element
+    -- sequence indicating the image's "alt" text label; if absent, the
+    -- label is understood to be the URL itself.
+    | EEmoji Text
+    -- ^ An emoji reference. The text here includes only the text
+    -- portion, not the colons, e.g. "foo" instead of ":foo:".
+    deriving (Show, Eq)
+
+-- | Element visual styles.
+data ElementStyle =
+    Normal
+    -- ^ Normal text
+    | Emph
+    -- ^ Emphasized text
+    | Strong
+    -- ^ Bold text
+    | Code
+    -- ^ Inline code segment or code block
+    | Hyperlink URL ElementStyle
+    -- ^ A terminal hyperlink to the specified URL, composed with
+    -- another element style
+    deriving (Eq, Show)
+
+parseMarkdown :: T.Text -> Seq RichTextBlock
+parseMarkdown t = fromMarkdownBlocks bs where C.Doc _ bs = C.markdown C.def t
+
+-- | Convert a sequence of markdown (Cheapskate) blocks into rich text
+-- blocks.
+fromMarkdownBlocks :: C.Blocks -> Seq RichTextBlock
+fromMarkdownBlocks = fmap fromMarkdownBlock
+
+-- | Convert a single markdown block into a single rich text block.
+fromMarkdownBlock :: C.Block -> RichTextBlock
+fromMarkdownBlock (C.Para is) =
+    Para $ fromMarkdownInlines is
+fromMarkdownBlock (C.Header level is) =
+    Header level $ fromMarkdownInlines is
+fromMarkdownBlock (C.Blockquote bs) =
+    Blockquote $ fromMarkdownBlock <$> bs
+fromMarkdownBlock (C.List f ty bss) =
+    List f (fromMarkdownListType ty) $ fmap fromMarkdownBlock <$> Seq.fromList bss
+fromMarkdownBlock (C.CodeBlock attr body) =
+    CodeBlock (fromMarkdownCodeAttr attr) body
+fromMarkdownBlock (C.HtmlBlock body) =
+    HTMLBlock body
+fromMarkdownBlock C.HRule =
+    HRule
+
+fromMarkdownCodeAttr :: C.CodeAttr -> CodeBlockInfo
+fromMarkdownCodeAttr (C.CodeAttr lang info) =
+    let strippedLang = T.strip lang
+        strippedInfo = T.strip info
+        maybeText t = if T.null t then Nothing else Just t
+    in CodeBlockInfo (maybeText strippedLang)
+                     (maybeText strippedInfo)
+
+fromMarkdownListType :: C.ListType -> ListType
+fromMarkdownListType (C.Bullet c) =
+    Bullet c
+fromMarkdownListType (C.Numbered wrap i) =
+    let dec = case wrap of
+                  C.PeriodFollowing -> Period
+                  C.ParenFollowing -> Paren
+    in Numbered dec i
+
+-- | Convert a sequence of Markdown inline values to a sequence of
+-- Elements.
+--
+-- This conversion converts sequences of Markdown AST fragments into
+-- RichText elements. In particular, this function may determine that
+-- some sequences of Markdown text fragments belong together, such as
+-- the sequence @["@", "joe", "-", "user"]@, which should be treated as
+-- a single "@joe-user" token due to username character validation. When
+-- appropriate, this function does such consolidation when converting to
+-- RichText elements.
+--
+-- This function is also partially responsible for paving the way for
+-- line-wrapping later on when RichText is rendered. This means that,
+-- when possible, the elements produced by this function need to be as
+-- small as possible, without losing structure information. An example
+-- of this is Markdown inline code fragments, such as "`this is code`".
+-- This function will convert that one Markdown inline code fragment
+-- into a sequence of five RichText elements, each with a "Code" style
+-- assigned: @[EText "this", ESpace, EText "is", ESpace, EText "code"]@.
+-- This "flattening" of the original Markdown structure makes it much
+-- easier to do line-wrapping without losing style information because
+-- it is possible to gather up tokens that do not exceed line widths
+-- without losing style information. This is key to rendering the text
+-- with the right terminal attributes.
+--
+-- However, there are a couple of cases where such flattening does *not*
+-- happen: hyperlinks and images. In these cases we do not flatten the
+-- (arbitrary) text label structure of links and images because we need
+-- to be able to recover those labels to gather up URLs to show to the
+-- user in the URL list. So we leave the complete text structure of
+-- those labels behind in the 'EHyperlink' and 'EImage' constructors as
+-- sequences of Elements. This means that logic in 'Draw.RichText' that
+-- does line-wrapping will have to explicitly break up link and image
+-- labels across line breaks.
+fromMarkdownInlines :: Seq C.Inline -> Seq Element
+fromMarkdownInlines inlines =
+    let go sty is = case Seq.viewl is of
+          C.Str ":" :< xs ->
+              let validEmojiFragment (C.Str f) =
+                      f `elem` ["_", "-"] || T.all isAlphaNum f
+                  validEmojiFragment _ = False
+                  (emojiFrags, rest) = Seq.spanl validEmojiFragment xs
+                  em = T.concat $ unsafeGetStr <$> F.toList emojiFrags
+              in case Seq.viewl rest of
+                  C.Str ":" :< rest2 ->
+                      Element Normal (EEmoji em) <| go sty rest2
+                  _ ->
+                      Element sty (EText ":") <| go sty xs
+          C.Str t :< xs | userSigil `T.isPrefixOf` t ->
+              let (uFrags, rest) = Seq.spanl isNameFragment xs
+                  t' = T.concat $ t : (unsafeGetStr <$> F.toList uFrags)
+                  u = T.drop 1 t'
+              in Element sty (EUser u) <| go sty rest
+          C.Str t :< xs | normalChannelSigil `T.isPrefixOf` t ->
+              let (cFrags, rest) = Seq.spanl isNameFragment xs
+                  cn = T.drop 1 $ T.concat $ t : (unsafeGetStr <$> F.toList cFrags)
+              in Element sty (EChannel cn) <| go sty rest
+          C.Str t :< xs ->
+              -- When we encounter a string node, we go ahead and
+              -- process the rest of the nodes in the sequence. If the
+              -- new sequence starts with *another* string node with
+              -- the same style, we merge them. We do this because
+              -- Cheapskate will parse things like punctuation as
+              -- individual string nodes, but we want to keep those
+              -- together with any text is adjacent to them to avoid
+              -- e.g. breaking up quotes from quoted text when doing
+              -- line-wrapping. It's important to make sure we only do
+              -- this for adjacent string (i.e. not whitespace) nodes
+              -- and that we make sure we only merge when they have the
+              -- same style.
+              let rest = go sty xs
+                  e = Element sty (EText t)
+              in case Seq.viewl rest of
+                  Element sty2 (EText t2) :< tail_ | sty2 == sty ->
+                      (Element sty (EText (t <> t2))) <| tail_
+                  _ ->
+                      e <| rest
+          C.Space :< xs ->
+              Element sty ESpace <| go sty xs
+          C.SoftBreak :< xs ->
+              Element sty ESoftBreak <| go sty xs
+          C.LineBreak :< xs ->
+              Element sty ELineBreak <| go sty xs
+          C.Link label theUrl _ :< xs ->
+              let mLabel = if Seq.null label
+                           then Nothing
+                           else Just $ fromMarkdownInlines label
+                  url = URL theUrl
+              in (Element (Hyperlink url sty) $ EHyperlink url mLabel) <| go sty xs
+          C.Image altIs theUrl _ :< xs ->
+              let mLabel = if Seq.null altIs
+                           then Nothing
+                           else Just $ fromMarkdownInlines altIs
+                  url = URL theUrl
+              in (Element (Hyperlink url sty) $ EImage url mLabel) <| go sty xs
+          C.RawHtml t :< xs ->
+              Element sty (ERawHtml t) <| go sty xs
+          C.Code t :< xs ->
+              -- We turn a single code string into individual Elements
+              -- so we can perform line-wrapping on the inline code
+              -- text.
+              let ts = [ Element Code frag
+                       | wd <- T.split (== ' ') t
+                       , frag <- case wd of
+                           "" -> [ESpace]
+                           _  -> [ESpace, EText wd]
+                       ]
+                  ts' = case ts of
+                    (Element _ ESpace:rs) -> rs
+                    _                     -> ts
+              in Seq.fromList ts' <> go sty xs
+          C.Emph as :< xs ->
+              go Emph as <> go sty xs
+          C.Strong as :< xs ->
+              go Strong as <> go sty xs
+          C.Entity t :< xs ->
+              Element sty (EText t) <| go sty xs
+          Seq.EmptyL -> mempty
+
+    in go Normal inlines
+
+unsafeGetStr :: C.Inline -> Text
+unsafeGetStr (C.Str t) = t
+unsafeGetStr _ = error "BUG: unsafeGetStr called on non-Str Inline"
+
+-- | Obtain all username references in a sequence of rich text blocks.
+findUsernames :: Seq RichTextBlock -> S.Set T.Text
+findUsernames = S.unions . F.toList . fmap blockFindUsernames
+
+blockFindUsernames :: RichTextBlock -> S.Set T.Text
+blockFindUsernames (Para is) =
+    elementFindUsernames $ F.toList is
+blockFindUsernames (Header _ is) =
+    elementFindUsernames $ F.toList is
+blockFindUsernames (Blockquote bs) =
+    findUsernames bs
+blockFindUsernames (List _ _ bs) =
+    S.unions $ F.toList $ findUsernames <$> bs
+blockFindUsernames _ =
+    mempty
+
+elementFindUsernames :: [Element] -> S.Set T.Text
+elementFindUsernames [] = mempty
+elementFindUsernames (e : es) =
+    case eData e of
+        EUser u -> S.insert u $ elementFindUsernames es
+        _ -> elementFindUsernames es
+
+-- | Obtain all URLs (and optional labels) in a rich text block.
+blockGetURLs :: RichTextBlock -> [(URL, Maybe (Seq Element))]
+blockGetURLs (Para is) =
+    catMaybes $ elementGetURL <$> toList is
+blockGetURLs (Header _ is) =
+    catMaybes $ elementGetURL <$> toList is
+blockGetURLs (Blockquote bs) =
+    mconcat $ blockGetURLs <$> toList bs
+blockGetURLs (List _ _ bss) =
+    mconcat $ mconcat $
+    (fmap blockGetURLs . F.toList) <$> F.toList bss
+blockGetURLs _ =
+    mempty
+
+elementGetURL :: Element -> Maybe (URL, Maybe (Seq Element))
+elementGetURL (Element _ (EHyperlink url label)) =
+    Just (url, label)
+elementGetURL (Element _ (EImage url label)) =
+    Just (url, label)
+elementGetURL _ =
+    Nothing
+
+-- | Find the first code block in a sequence of rich text blocks.
+findVerbatimChunk :: Seq RichTextBlock -> Maybe Text
+findVerbatimChunk = getFirst . F.foldMap go
+  where go (CodeBlock _ t) = First (Just t)
+        go _               = First Nothing
+
+isValidNameChar :: Char -> Bool
+isValidNameChar c = isAlpha c || c == '_' || c == '.' || c == '-'
+
+isNameFragment :: C.Inline -> Bool
+isNameFragment (C.Str t) =
+    not (T.null t) && isValidNameChar (T.head t)
+isNameFragment _ = False
diff --git a/src/Types/UserNames.hs b/src/Types/UserNames.hs
deleted file mode 100644
--- a/src/Types/UserNames.hs
+++ /dev/null
@@ -1,70 +0,0 @@
-module Types.UserNames
-  ( findUsernames
-  , isNameFragment
-  , takeWhileNameFragment
-  )
-where
-
-import qualified Cheapskate as C
-import           Data.Char ( isAlpha )
-import qualified Data.Foldable as F
-import qualified Data.Set as S
-import qualified Data.Text as T
-
-import           Prelude ()
-import           Prelude.MH
-
-
-findUsernames :: C.Blocks -> S.Set T.Text
-findUsernames = S.unions . F.toList . fmap blockFindUsernames
-
-blockFindUsernames :: C.Block -> S.Set T.Text
-blockFindUsernames (C.Para is) =
-    inlineFindUsernames $ F.toList is
-blockFindUsernames (C.Header _ is) =
-    inlineFindUsernames $ F.toList is
-blockFindUsernames (C.Blockquote bs) =
-    findUsernames bs
-blockFindUsernames (C.List _ _ bs) =
-    S.unions $ F.toList $ findUsernames <$> bs
-blockFindUsernames _ =
-    mempty
-
-inlineFindUsernames :: [C.Inline] -> S.Set T.Text
-inlineFindUsernames [] = mempty
-inlineFindUsernames (C.Str "@" : rest) =
-    let (strs, remaining) = takeWhileNameFragment rest
-    in if null strs
-       then inlineFindUsernames remaining
-       else S.insert (T.concat $ getInlineStr <$> strs) $ inlineFindUsernames remaining
-inlineFindUsernames (_ : rest) =
-    inlineFindUsernames rest
-
-getInlineStr :: C.Inline -> T.Text
-getInlineStr (C.Str s) = s
-getInlineStr _ = ""
-
-takeWhileNameFragment :: [C.Inline] -> ([C.Inline], [C.Inline])
-takeWhileNameFragment [] = ([], [])
-takeWhileNameFragment rest =
-    let (strs, remaining) = break (not . isNameFragment) rest
-        -- Does the last element in strs start with a letter? If
-        -- not, move it to the remaining list. This avoids pulling
-        -- punctuation-only tokens into usernames, e.g. "Hello,
-        -- @foobar."
-        (strs', remaining') =
-            if length strs <= 1
-            then (strs, remaining)
-            else let (initStrs, [lastStr]) = splitAt (length strs - 1) strs
-                 in if isAlpha $ T.head $ getInlineStr lastStr
-                    then (strs, remaining)
-                    else (initStrs, lastStr : remaining)
-    in (strs', remaining')
-
-isValidNameChar :: Char -> Bool
-isValidNameChar c = isAlpha c || c == '_' || c == '.' || c == '-'
-
-isNameFragment :: C.Inline -> Bool
-isNameFragment (C.Str t) =
-    not (T.null t) && isValidNameChar (T.head t)
-isNameFragment _ = False
diff --git a/src/Types/Users.hs b/src/Types/Users.hs
--- a/src/Types/Users.hs
+++ b/src/Types/Users.hs
@@ -13,7 +13,6 @@
   , userInfoFromUser
   -- * Miscellaneous
   , getUsernameSet
-  , userSigil
   , trimUserSigil
   , statusFromText
   , findUserById
@@ -43,6 +42,7 @@
 import           Network.Mattermost.Types ( UserId(..), User(..) )
 
 import           Types.Common
+import           Constants ( userSigil )
 
 -- * 'UserInfo' Values
 
@@ -184,9 +184,6 @@
   case filter ((== (Just $ trimUserSigil nick)) . _uiNickName . snd) $ HM.toList $ _ofUsers us of
     (pair : []) -> Just pair
     _ -> Nothing
-
-userSigil :: Text
-userSigil = "@"
 
 trimUserSigil :: Text -> Text
 trimUserSigil n
diff --git a/src/Windows/ViewMessage.hs b/src/Windows/ViewMessage.hs
--- a/src/Windows/ViewMessage.hs
+++ b/src/Windows/ViewMessage.hs
@@ -25,7 +25,7 @@
 import           Events.Keybindings
 import           Themes
 import           Types
-import           Markdown
+import           Draw.RichText
 import           Draw.Messages ( nameForUserRef )
 
 -- | The template for "View Message" windows triggered by message
@@ -165,6 +165,12 @@
 
        , mkKb PageDownEvent "Page down" $
            mh $ vScrollBy vs pageAmount
+
+       , mkKb PageLeftEvent "Page left" $
+           mh $ hScrollBy vs (-2 * pageAmount)
+
+       , mkKb PageRightEvent "Page right" $
+           mh $ hScrollBy vs (2 * pageAmount)
 
        , mkKb ScrollUpEvent "Scroll up" $
            mh $ vScrollBy vs (-1)
diff --git a/test/Message_QCA.hs b/test/Message_QCA.hs
--- a/test/Message_QCA.hs
+++ b/test/Message_QCA.hs
@@ -15,6 +15,7 @@
 import Test.Tasty.QuickCheck
 import Types.Messages
 import Types.Posts
+import Types.RichText
 
 genMap :: Ord key => Gen key -> Gen value -> Gen (Map key value)
 genMap gk gv = let kv = (,) <$> gk <*> gv in fromList <$> listOf kv
@@ -30,7 +31,7 @@
 
 genMessage :: Gen Message
 genMessage = Message
-             <$> genBlocks
+             <$> (fromMarkdownBlocks <$> genBlocks)
              <*> genText
              <*> genUserRef
              <*> genTime
@@ -58,7 +59,7 @@
 genMessage__DeletedPost :: Gen Message__DeletedPost
 genMessage__DeletedPost = Message__DeletedPost
                           <$> (Message
-                              <$> genBlocks
+                              <$> (fromMarkdownBlocks <$> genBlocks)
                               <*> genText
                               <*> genUserRef
                               <*> genTime
@@ -80,7 +81,7 @@
 genMessage__Posted :: Gen Message__Posted
 genMessage__Posted = Message__Posted
                      <$> (Message
-                         <$> genBlocks
+                         <$> (fromMarkdownBlocks <$> genBlocks)
                          <*> genText
                          <*> genUserRef
                          <*> genTime