diff --git a/lgtk.cabal b/lgtk.cabal
--- a/lgtk.cabal
+++ b/lgtk.cabal
@@ -1,16 +1,16 @@
 name:               lgtk
-version:            0.5
+version:            0.5.1
 category:           GUI
 synopsis:           lens-based API for Gtk
 description:
     The main interface module of LGtk is "LGtk".
     .
-    See also <http://people.inf.elte.hu/divip/LGtk/index.html>
+    See also <http://www.haskell.org/haskellwiki/LGtk>
 stability:          experimental
 license:            BSD3
 license-file:       LICENSE
 author:             Péter Diviánszky
-homepage:           http://people.inf.elte.hu/divip/LGtk/index.html
+homepage:           http://www.haskell.org/haskellwiki/LGtk
 bug-reports:        http://hub.darcs.net/divip/lgtk/issues
 maintainer:         divipp@gmail.com
 cabal-version:      >= 1.8
diff --git a/src/Control/Monad/EffRef.hs b/src/Control/Monad/EffRef.hs
--- a/src/Control/Monad/EffRef.hs
+++ b/src/Control/Monad/EffRef.hs
@@ -31,21 +31,33 @@
 
     {- |
     Let @r@ be an effectless action (@ReadRef@ guarantees this).
-    @onChange r fmm@ has the following effect:
 
+    @(onChange init r fmm)@ has the following effect:
+
     Whenever the value of @r@ changes (with respect to the given equality),
     @fmm@ is called with the new value @a@.
-    The value of the @fmm a@ action is memoized,
+    The value of the @(fmm a)@ action is memoized,
     but the memoized value is run again and again.
 
+    The boolean parameter @init@ tells whether the action should
+    be run in the beginning or not.
+
     For example, let @(k :: a -> m b)@ and @(h :: b -> m ())@,
-    and suppose that @r@ will have values @a1@, @a2@, @a3@ = @a1@.
+    and suppose that @r@ will have values @a1@, @a2@, @a3@ = @a1@, @a4@ = @a2@.
 
-    @onChange r $ \\a -> k a >>= return . h@
+    @onChange True r $ \\a -> k a >>= return . h@
 
     has the effect
 
-    @k a1 >>= \\b1 -> h b1 >> k a2 >>= \\b2 -> h b2 >> h b1@
+    @k a1 >>= \\b1 -> h b1 >> k a2 >>= \\b2 -> h b2 >> h b1 >> h b2@
+
+    and
+
+    @onChange False r $ \\a -> k a >>= return . h@
+
+    has the effect
+
+    @k a2 >>= \\b2 -> h b2 >> k a1 >>= \\b1 -> h b1 >> h b2@
     -}
     onChange :: Eq a => Bool -> ReadRef m a -> (a -> m (m ())) -> m ()
 
@@ -78,7 +90,7 @@
     asyncWrite :: Eq a => Int -> (a -> WriteRef m ()) -> a -> m ()
 
     {- |
-    @fileRef path@ returns a reference which holds the actual contents
+    @(fileRef path)@ returns a reference which holds the actual contents
     of the file accessed by @path@.
 
     When the value of the reference changes, the file changes.
@@ -97,7 +109,7 @@
     putStr_    :: String -> m ()
 
     {- | Read a line from the standard input device.
-    @getLine_ f@ returns immediately. When the line @s@ is read,
+    @(getLine_ f)@ returns immediately. When the line @s@ is read,
     @f s@ is called.
     -}
     getLine_   :: (String -> WriteRef m ()) -> m ()
diff --git a/src/Control/Monad/ExtRef.hs b/src/Control/Monad/ExtRef.hs
--- a/src/Control/Monad/ExtRef.hs
+++ b/src/Control/Monad/ExtRef.hs
@@ -10,13 +10,14 @@
 
     -- * Reference class
     , Reference (..)
+    , ReadRefMonad
 
     -- * Ref construction class
     , ExtRef (..)
-
-    -- * Derived constructs
     , ReadRef
     , WriteRef
+
+    -- * Derived constructs
     , modRef
     , liftReadRef
     , readRef'
@@ -68,7 +69,7 @@
 
     Property derived from the 'HasReadPart' instance:
 
-    @ReadPart (Refmonad r)@  ===  @Reader s@
+    @ReadRefMonad r@ = @ReadPart (Refmonad r)@  ===  @Reader s@
     -}
     type RefMonad r :: * -> *
 
@@ -78,7 +79,7 @@
 
     @(readRef r >> return ())@ === @return ()@
     -}
-    readRef  :: r a -> ReadPart (RefMonad r) a
+    readRef  :: r a -> ReadRefMonad r a
 
     {- | @writeRef r@ === @modify . setL r@
 
@@ -104,11 +105,13 @@
 
     @joinRef@ === @Lens . join . (runLens .) . runReader@
     -}
-    joinRef :: ReadPart (RefMonad r) (r a) -> r a
+    joinRef :: ReadRefMonad r (r a) -> r a
 
     -- | @unitRef@ === @lens (const ()) (const id)@
     unitRef :: r ()
 
+type ReadRefMonad m = ReadPart (RefMonad m)
+
 infixr 8 `lensMap`
 
 -- | @modRef r f@ === @liftReadPart (readRef r) >>= writeRef r . f@
@@ -160,7 +163,7 @@
 
 type WriteRef m = RefMonad (Ref m)
 
-type ReadRef m = ReadPart (RefMonad (Ref m))
+type ReadRef m = ReadRefMonad (Ref m)
 
 {- | @ReadRef@ lifted to the reference creation class.
 
@@ -275,13 +278,29 @@
 
 data EqRef_ r a = forall b . Eq b => EqRef_ (r b) (Lens b a)
 
--- | References with inherent equivalence
-newtype EqRef r a = EqRef { runEqRef :: ReadPart (RefMonad r) (EqRef_ r a) }
+{- | References with inherent equivalence.
 
--- | @hasEffect@ is correct only if @eqRef@ is applied on a pure reference (a reference which is a pure lens on the hidden state).
+@EqRef r a@ === @ReadRefMonad r (forall b . Eq b => (Lens b a, r b))@
+
+As a reference, @(m :: EqRef r a)@ behaves as
+
+@joinRef $ liftM (uncurry lensMap) m@
+
+@EqRef@ makes defining auto-sensitive buttons easier, see later.
+-}
+newtype EqRef r a = EqRef { runEqRef :: ReadRefMonad r (EqRef_ r a) }
+
+{- | @EqRef@ construction.
+
+@hasEffect@ is correct only if @eqRef@ is applied on a pure reference (a reference which is a pure lens on the hidden state).
+-}
 eqRef :: (Reference r, Eq a) => r a -> EqRef r a
 eqRef r = EqRef $ return $ EqRef_ r id
 
+{- | An @EqRef@ is a normal reference if we forget about the equality.
+
+@toRef m@ === @joinRef $ liftM (uncurry lensMap) m@
+-}
 toRef :: Reference r => EqRef r a -> r a
 toRef (EqRef m) = joinRef $ liftM (\(EqRef_ r k) -> k `lensMap` r) m
 
@@ -290,7 +309,7 @@
     :: Reference r
     => EqRef r a
     -> (a -> a)
-    -> ReadPart (RefMonad r) Bool
+    -> ReadRefMonad r Bool
 hasEffect m f = runEqRef m >>= \(EqRef_ r k) -> liftM (\x -> modL k f x /= x) $ readRef r
 
 
diff --git a/src/Control/Monad/Restricted.hs b/src/Control/Monad/Restricted.hs
--- a/src/Control/Monad/Restricted.hs
+++ b/src/Control/Monad/Restricted.hs
@@ -23,6 +23,7 @@
 import Control.Monad.RWS
 import Control.Monad.Trans.Identity
 import qualified System.Environment as Env
+import System.IO.Error (catchIOError, isDoesNotExistError)
 
 {- |
 Monad morphism. Think as @m@ is a submonad of @n@.
@@ -35,12 +36,12 @@
 -}
 newtype MorphD m n = MorphD { runMorphD :: Morph m n }
 
--- | @m@ is a monad which has a submonad @ReadPart m@ which is isomorphic to 'Reader'.
+-- | @m@ has a submonad @(ReadPart m)@ which is isomorphic to 'Reader'.
 class (Monad m, Monad (ReadPart m)) => HasReadPart m where
 
     {- | Law: @(ReadPart m)@  ===  @('Reader' x)@ for some @x@.
 
-    Alternative laws which ensures this isomorphism (@r :: ReadPart m a@ is arbitrary):
+    Alternative laws which ensures this isomorphism (@r :: (ReadPart m a)@ is arbitrary):
 
      *  @(r >> return ())@ === @return ()@
 
@@ -50,7 +51,7 @@
     -}
     type ReadPart m :: * -> *
 
-    -- | @ReadPart m@ is a submonad of @m@
+    -- | @(ReadPart m)@ is a submonad of @m@
     liftReadPart :: Morph (ReadPart m) m
 
 -- | @ReadPart (StateT s m) = Reader s@ 
@@ -95,7 +96,7 @@
     -- | The name of the program as it was invoked.
     getProgName :: m String
 
-    -- | @getEnv var@ returns the value of the environment variable @var@.
+    -- | @(lookupEnv var)@ returns the value of the environment variable @var@.
     lookupEnv   :: String -> m (Maybe String)
 
 -- | This instance is used in the implementation, the end users do not need it.
@@ -103,7 +104,9 @@
 
     getArgs     = Env.getArgs
     getProgName = Env.getProgName
-    lookupEnv   = Env.lookupEnv
+--    lookupEnv   = Env.lookupEnv -- does not work with Haskell Platform 2013.2.0.0
+    lookupEnv v = catchIOError (liftM Just $ Env.getEnv v) $ \e ->
+        if isDoesNotExistError e then return Nothing else ioError e
 
 -- | This instance is used in the implementation, the end users do not need it.
 instance SafeIO m => SafeIO (Ext n m) where
diff --git a/src/LGtk.hs b/src/LGtk.hs
--- a/src/LGtk.hs
+++ b/src/LGtk.hs
@@ -6,10 +6,19 @@
 -- | Main LGtk interface.
 module LGtk
     ( 
-    -- * Categories
+    -- * Re-export
+
+    -- ** Category
       Category (..)
+
+    -- ** Tensor
     , Tensor (..)
+
+    -- ** Monad
     , liftM
+    , liftM2
+    , liftM3
+    , when
 
     -- * Lenses
     -- ** Construction
@@ -40,6 +49,7 @@
     -- ** Basic operations
     , Reference
     , RefMonad
+    , ReadRefMonad
     , readRef
     , writeRef
     , lensMap
@@ -93,13 +103,13 @@
 
     -- ** GUI descriptions
     , label
-    , button_
-    , Color (..)
     , checkbox
     , combobox
     , entry
     , vcat
     , hcat
+    , button_
+    , Color (..)
     , notebook
     , cell_
     , action
@@ -143,7 +153,7 @@
 Construction of a @(w :: forall m . EffIORef m => Widget m)@ value is side-effect free,
 side-effects happen at running @('runWidget' w)@.
 
-@Widget m@ should be abstract, but it is also safe to keep it as a type synonym because
+@Widget@ should be abstract data type, but it is also safe to keep it as a type synonym because
 the operations of the revealed implementation are hidden.
 -}
 type Widget m = Gtk.Widget (EffectM m) m
diff --git a/src/LGtk/ADTEditor.hs b/src/LGtk/ADTEditor.hs
--- a/src/LGtk/ADTEditor.hs
+++ b/src/LGtk/ADTEditor.hs
@@ -1,11 +1,9 @@
 {-# LANGUAGE MultiParamTypeClasses #-}
-{-# LANGUAGE FlexibleInstances #-}
-{-# LANGUAGE FlexibleContexts #-}
 {-# LANGUAGE GADTs #-}
 {-# LANGUAGE TypeFamilies #-}
 {-# LANGUAGE KindSignatures #-}
-{-# LANGUAGE ConstraintKinds #-}
 {-# LANGUAGE DataKinds #-}
+-- | A generic ADT editor defined on top of the main LGtk interface, "LGtk".
 module LGtk.ADTEditor
     ( List (..), Elems(..), ADTLens(..)
     , adtEditor
@@ -13,7 +11,6 @@
 
 import LGtk
 
-import Control.Monad
 import Prelude hiding ((.), id)
 
 -- | Type-level lists
@@ -24,9 +21,43 @@
     ElemsNil :: Elems Nil
     ElemsCons :: ADTLens a => a -> Elems as -> Elems (Cons a as)
 
--- | Lens for editable ADTs
+{- | Lens for editable ADTs with support of shared record fields between constructors.
+
+Suppose we have the data type
+
+@
+data X
+    = X1 { a :: Int, b :: Bool }
+    | X2 { a :: Int, c :: Char }
+@
+
+We can build an editor which can switch between two editor for the constructors.
+If the field @a@ is edited in one editor, it will be updated in the other.
+-}
 class ADTLens a where
+
+    {- | @ADTEls a@ is the list of types of the parts of the ADT.
+
+    For example,
+
+    @ADTEls X = Cons Int (Cons Bool (Cons Char Nil))@
+    -}
     type ADTEls a :: List *
+
+    {- | The lens which defines an abstract editor.
+
+    The first parameter defines the displayed constructor name and the parts of the constructor for each constructor.
+    @Int@ is an index in the @ADTEls@ list.
+
+    For example, in case of @X@,
+
+    @fst3 adtLens = [(\"X1\", [0, 1]), (\"X2\", [0, 2])]@
+
+    The second parameter is the list of default values for each part.
+
+    The third parameter is a lens from the selected constructor index plus
+    the values of the ADT parts to the ADT values.
+    -}
     adtLens :: ([(String, [Int])], Elems (ADTEls a), Lens (Int, Elems (ADTEls a)) a)
 
 -- | A generic ADT editor
diff --git a/src/LGtk/Demos/IntListEditor.hs b/src/LGtk/Demos/IntListEditor.hs
--- a/src/LGtk/Demos/IntListEditor.hs
+++ b/src/LGtk/Demos/IntListEditor.hs
@@ -22,7 +22,7 @@
                 [ entryShow $ toRef len
                 , smartButton (return "+1") len (+1)
                 , smartButton (return "-1") len (+(-1))
-                , smartButton (liftM (("DeleteAll " ++) . show) $ readRef $ toRef len) len $ const 0
+                , smartButton (liftM (("DeleteAll " ++) . show) $ readRef len) len $ const 0
                 , button (return "undo") undo
                 , button (return "redo") redo
                 ]
diff --git a/src/LGtk/Demos/Main.hs b/src/LGtk/Demos/Main.hs
--- a/src/LGtk/Demos/Main.hs
+++ b/src/LGtk/Demos/Main.hs
@@ -2,8 +2,7 @@
     ( main
     ) where
 
-import Control.Monad
-import Data.Maybe
+import Data.Maybe (isJust)
 import Prelude hiding (id, (.))
 
 import LGtk
@@ -43,7 +42,7 @@
             let (a, b) = interval ab
             c <- counter 0 ab
             return $ vcat
-                [ label $ liftM show $ readRef $ toRef c
+                [ label $ liftM show $ readRef c
                 , hcat
                     [ smartButton (return "+1") c (+1)
                     , smartButton (return "-1") c (+(-1))
diff --git a/src/LGtk/Demos/TEditor.hs b/src/LGtk/Demos/TEditor.hs
--- a/src/LGtk/Demos/TEditor.hs
+++ b/src/LGtk/Demos/TEditor.hs
@@ -1,11 +1,8 @@
 {-# LANGUAGE GADTs #-}
 {-# LANGUAGE TypeFamilies #-}
 {-# LANGUAGE DataKinds #-}
-{-# LANGUAGE ConstraintKinds #-}
-{-# LANGUAGE FlexibleContexts #-}
 module LGtk.Demos.TEditor where
 
-import Control.Monad
 import Prelude hiding ((.), id)
 
 import LGtk
diff --git a/src/LGtk/Demos/Tri.hs b/src/LGtk/Demos/Tri.hs
--- a/src/LGtk/Demos/Tri.hs
+++ b/src/LGtk/Demos/Tri.hs
@@ -1,6 +1,3 @@
-{-# LANGUAGE FlexibleContexts #-}
-{-# LANGUAGE TypeFamilies #-}
-{-# LANGUAGE ConstraintKinds #-}
 {- |
 An editor for integers x, y, z such that x + y = z always hold and
 the last edited value change.
@@ -9,7 +6,6 @@
 
 import LGtk
 
-import Control.Monad
 import Prelude hiding ((.), id)
 
 -- | Information pieces: what is known?
@@ -32,8 +28,8 @@
 tri = action $ do
     s <- newRef [X 0, Y 0]
     return $ vcat
-        [ hcat [entryShow $ lens getX setX `lensMap` s, label $ return "x"]
-        , hcat [entryShow $ lens getY setY `lensMap` s, label $ return "y"]
+        [ hcat [entryShow $ lens getX  setX  `lensMap` s, label $ return "x"]
+        , hcat [entryShow $ lens getY  setY  `lensMap` s, label $ return "y"]
         , hcat [entryShow $ lens getXY setXY `lensMap` s, label $ return "x + y"]
         ]