diff --git a/CHANGELOG.md b/CHANGELOG.md
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,8 +1,19 @@
 
+0.3.0.0
+=======
+
+* Added support in `Input.Mouse` for parsing horizontal scrolling inputs
+  to work with Vty 6.6.
+* Improved the `vty-unix-build-width-table` tool (thanks Eric Mertens)
+  to make it more robust when the terminal fails to recognize the
+  `getCursorPosition` escape sequence.
+
 0.2.0.0
 =======
 
 API changes:
+* The `buildOutput` function in `Graphics.Vty.Platform.Unix.Output` now
+  takes a new first argument of type `VtyUserConfig`.
 * The `settingColorMode` field of `UnixSettings` was removed in favor of
   Vty 6.1's new `configPreferredColorMode` field of the `VtyUserConfig`
   type. This package now uses that setting if present; otherwise it does
diff --git a/src/Graphics/Vty/Platform/Unix/Input/Mouse.hs b/src/Graphics/Vty/Platform/Unix/Input/Mouse.hs
--- a/src/Graphics/Vty/Platform/Unix/Input/Mouse.hs
+++ b/src/Graphics/Vty/Platform/Unix/Input/Mouse.hs
@@ -83,12 +83,20 @@
 rightButton :: Int
 rightButton = 2
 
+-- | See https://invisible-island.net/xterm/ctlseqs/ctlseqs.html#h3-Wheel-mice
 scrollUp :: Int
 scrollUp = 64
 
 scrollDown :: Int
 scrollDown = 65
 
+-- | See https://invisible-island.net/xterm/ctlseqs/ctlseqs.html#h3-Other-buttons
+scrollLeft :: Int
+scrollLeft = 66
+
+scrollRight :: Int
+scrollRight = 67
+
 hasBitSet :: Int -> Int -> Bool
 hasBitSet val bit = val .&. bit > 0
 
@@ -113,6 +121,8 @@
                     , (rightButton,  BRight)
                     , (scrollUp,     BScrollUp)
                     , (scrollDown,   BScrollDown)
+                    , (scrollLeft,   BScrollLeft)
+                    , (scrollRight,  BScrollRight)
                     ]
     in case lookup (mods .&. buttonMask) buttonMap of
         Nothing -> failParse
diff --git a/tools/BuildWidthTable.hs b/tools/BuildWidthTable.hs
--- a/tools/BuildWidthTable.hs
+++ b/tools/BuildWidthTable.hs
@@ -1,18 +1,29 @@
-{-# LANGUAGE ScopedTypeVariables #-}
-{-# LANGUAGE CPP #-}
-module Main where
+module Main (main) where
 
+import Graphics.Vty.UnicodeWidthTable.Main (defaultMain)
 import System.Console.ANSI (getCursorPosition)
-import Text.Printf (printf)
 
-import Graphics.Vty.UnicodeWidthTable.Main (defaultMain)
+main :: IO ()
+main = defaultMain charWidth
 
+-- | The number of times we'll attempt to compute a character's width
+-- before defaulting to @1@ and continuing.
+attempts :: Int
+attempts = 3
+
+-- | Experimentally determine the console width of the character.
 charWidth :: Char -> IO Int
-charWidth c = do
-    printf "\r"
-    putChar c
-    Just (_, col) <- getCursorPosition
-    return col
+charWidth = charWidth' 0
 
-main :: IO ()
-main = defaultMain charWidth
+-- | Helper for 'charWidth' with the number of failed attempts counted.
+charWidth' :: Int {- ^ failed attempts -} -> Char -> IO Int
+charWidth' n c
+    | n >= attempts =
+     do putStrLn ("\rUnable to check: " ++ [c] ++ " (" ++ show c ++ ")")
+        pure 1 -- fallback default to 1
+    | otherwise =
+     do putStr ['\r', c]
+        mb <- getCursorPosition
+        case mb of
+            Nothing -> charWidth' (n+1) c
+            Just (_, col) -> pure col
diff --git a/vty-unix.cabal b/vty-unix.cabal
--- a/vty-unix.cabal
+++ b/vty-unix.cabal
@@ -1,6 +1,6 @@
 cabal-version:      3.0
 name:               vty-unix
-version:            0.2.0.0
+version:            0.3.0.0
 synopsis:           Unix backend for Vty
 description:        This package provides Unix terminal support for Vty.
 license:            BSD-3-Clause
@@ -53,7 +53,7 @@
                       mtl,
                       unix,
                       terminfo,
-                      vty >= 6.1,
+                      vty >= 6.6,
                       deepseq,
                       vector,
                       parsec,
@@ -74,6 +74,6 @@
   if !impl(ghc >= 8.0)
     build-depends:     semigroups >= 0.16
 
-  build-depends:       base,
+  build-depends:       base >= 4.8 && < 5,
                        vty,
                        ansi-terminal