diff --git a/c-src/Fl_File_InputC.cpp b/c-src/Fl_File_InputC.cpp
--- a/c-src/Fl_File_InputC.cpp
+++ b/c-src/Fl_File_InputC.cpp
@@ -454,10 +454,10 @@
   FL_EXPORT_C(void,Fl_File_Input_set_wrap)(fl_File_Input file_input,int b){
     (static_cast<Fl_File_Input*>(file_input))->wrap(b);
   }
-  FL_EXPORT_C(void,Fl_File_Input_tab_nav)(fl_File_Input file_input,int val){
+  FL_EXPORT_C(void,Fl_File_Input_set_tab_nav)(fl_File_Input file_input,int val){
     (static_cast<Fl_File_Input*>(file_input))->tab_nav(val);
   }
-  FL_EXPORT_C(int,Fl_File_Input_set_tab_nav)(fl_File_Input file_input){
+  FL_EXPORT_C(int,Fl_File_Input_tab_nav)(fl_File_Input file_input){
     return (static_cast<Fl_File_Input*>(file_input))->tab_nav();
   }
   FL_EXPORT_C(int,Fl_File_Input_set_value)(fl_File_Input file_input,const char* text){
diff --git a/c-src/Fl_File_InputC.h b/c-src/Fl_File_InputC.h
--- a/c-src/Fl_File_InputC.h
+++ b/c-src/Fl_File_InputC.h
@@ -151,8 +151,8 @@
   FL_EXPORT_C_HEADER(void,Fl_File_Input_set_readonly,(fl_File_Input file_input,int b));
   FL_EXPORT_C_HEADER(int,Fl_File_Input_wrap,(fl_File_Input file_input));
   FL_EXPORT_C_HEADER(void,Fl_File_Input_set_wrap,(fl_File_Input file_input,int b));
-  FL_EXPORT_C_HEADER(void,Fl_File_Input_tab_nav,(fl_File_Input file_input,int val));
-  FL_EXPORT_C_HEADER(int,Fl_File_Input_set_tab_nav,(fl_File_Input file_input));
+  FL_EXPORT_C_HEADER(void,Fl_File_Input_set_tab_nav,(fl_File_Input file_input,int val));
+  FL_EXPORT_C_HEADER(int,Fl_File_Input_tab_nav,(fl_File_Input file_input));
 
   /* Fl_File_Input specific functions */
   FL_EXPORT_C_HEADER(fl_File_Input,Fl_File_Input_New_WithLabel,(int x, int y, int w, int h, const char* label));
diff --git a/c-src/Fl_InputC.cpp b/c-src/Fl_InputC.cpp
--- a/c-src/Fl_InputC.cpp
+++ b/c-src/Fl_InputC.cpp
@@ -464,10 +464,10 @@
   FL_EXPORT_C(void,Fl_Input_set_wrap)(fl_Input input,int b){
     (static_cast<Fl_Input*>(input))->wrap(b);
   }
-  FL_EXPORT_C(void,Fl_Input_tab_nav)(fl_Input input,int val){
+  FL_EXPORT_C(void,Fl_Input_set_tab_nav)(fl_Input input,int val){
     (static_cast<Fl_Input*>(input))->tab_nav(val);
   }
-  FL_EXPORT_C(int,Fl_Input_set_tab_nav)(fl_Input input){
+  FL_EXPORT_C(int,Fl_Input_tab_nav)(fl_Input input){
     return (static_cast<Fl_Input*>(input))->tab_nav();
   }
   FL_EXPORT_C(void, Fl_Input_draw)(fl_Input o){
diff --git a/c-src/Fl_InputC.h b/c-src/Fl_InputC.h
--- a/c-src/Fl_InputC.h
+++ b/c-src/Fl_InputC.h
@@ -161,8 +161,8 @@
   FL_EXPORT_C_HEADER(void,Fl_Input_set_readonly,(fl_Input input,int b));
   FL_EXPORT_C_HEADER(int,Fl_Input_wrap,(fl_Input input));
   FL_EXPORT_C_HEADER(void,Fl_Input_set_wrap,(fl_Input input,int b));
-  FL_EXPORT_C_HEADER(void,Fl_Input_tab_nav,(fl_Input input,int val));
-  FL_EXPORT_C_HEADER(int,Fl_Input_set_tab_nav,(fl_Input input));
+  FL_EXPORT_C_HEADER(void,Fl_Input_set_tab_nav,(fl_Input input,int val));
+  FL_EXPORT_C_HEADER(int,Fl_Input_tab_nav,(fl_Input input));
   FL_EXPORT_C_HEADER(fl_Input,Fl_OverriddenInput_New,(int X, int Y, int W, int H,fl_Widget_Virtual_Funcs* fs));
   FL_EXPORT_C_HEADER(fl_Input,Fl_OverriddenInput_New_WithLabel,(int X, int Y, int W, int H, const char* label, fl_Widget_Virtual_Funcs* fs));
   FL_EXPORT_C_HEADER(void,Fl_Input_draw,(fl_Input o));
diff --git a/c-src/Fl_Input_C.cpp b/c-src/Fl_Input_C.cpp
--- a/c-src/Fl_Input_C.cpp
+++ b/c-src/Fl_Input_C.cpp
@@ -394,10 +394,10 @@
   FL_EXPORT_C(void,Fl_Input__set_wrap)(fl_Input_ input_,int b){
     (static_cast<Fl_Input_*>(input_))->wrap(b);
   }
-  FL_EXPORT_C(void,Fl_Input__tab_nav)(fl_Input_ input_,int val){
+  FL_EXPORT_C(void,Fl_Input__set_tab_nav)(fl_Input_ input_,int val){
     (static_cast<Fl_Input_*>(input_))->tab_nav(val);
   }
-  FL_EXPORT_C(int,Fl_Input__set_tab_nav)(fl_Input_ input_){
+  FL_EXPORT_C(int,Fl_Input__tab_nav)(fl_Input_ input_){
     return (static_cast<Fl_Input_*>(input_))->tab_nav();
   }
 #ifdef __cplusplus
diff --git a/c-src/Fl_Input_C.h b/c-src/Fl_Input_C.h
--- a/c-src/Fl_Input_C.h
+++ b/c-src/Fl_Input_C.h
@@ -147,8 +147,8 @@
   FL_EXPORT_C_HEADER(void,Fl_Input__set_readonly,(fl_Input_ input_,int b));
   FL_EXPORT_C_HEADER(int,Fl_Input__wrap,(fl_Input_ input_));
   FL_EXPORT_C_HEADER(void,Fl_Input__set_wrap,(fl_Input_ input_,int b));
-  FL_EXPORT_C_HEADER(void,Fl_Input__tab_nav,(fl_Input_ input_,int val));
-  FL_EXPORT_C_HEADER(int,Fl_Input__set_tab_nav,(fl_Input_ input_));
+  FL_EXPORT_C_HEADER(void,Fl_Input__set_tab_nav,(fl_Input_ input_,int val));
+  FL_EXPORT_C_HEADER(int,Fl_Input__tab_nav,(fl_Input_ input_));
 #ifdef __cplusplus
 }
 #endif
diff --git a/fltkhs.cabal b/fltkhs.cabal
--- a/fltkhs.cabal
+++ b/fltkhs.cabal
@@ -1,5 +1,5 @@
 name : fltkhs
-version : 0.5.4.2
+version : 0.5.4.3
 synopsis : FLTK bindings
 description: Low level bindings for the FLTK GUI toolkit. For installation and quick start instruction please scroll all the way down to the README.
 license : MIT
diff --git a/src/Graphics/UI/FLTK/LowLevel/FL.chs b/src/Graphics/UI/FLTK/LowLevel/FL.chs
--- a/src/Graphics/UI/FLTK/LowLevel/FL.chs
+++ b/src/Graphics/UI/FLTK/LowLevel/FL.chs
@@ -15,7 +15,7 @@
      ready,
      option,
      setOption,
-     addAwakeHandler,
+     addAwakeHandler_,
      getAwakeHandler_,
      display,
      ownColormap,
@@ -262,11 +262,12 @@
 
 {# fun Fl_add_awake_handler_ as addAwakeHandler'
   {id `FunPtr CallbackPrim', id `(Ptr ())'} -> `Int' #}
-addAwakeHandler :: GlobalCallback -> IO Int
-addAwakeHandler awakeHandler =
+addAwakeHandler_ :: GlobalCallback -> IO (Either AwakeRingFull ())
+addAwakeHandler_ awakeHandler =
     do
       callbackPtr <-  toGlobalCallbackPrim awakeHandler
-      addAwakeHandler' callbackPtr nullPtr
+      res <- addAwakeHandler' callbackPtr nullPtr
+      return (successOrAwakeRingFull res)
 
 {# fun Fl_get_awake_handler_ as getAwakeHandler_'
   {id `Ptr (FunPtr CallbackPrim)', id `Ptr (Ptr ())'} -> `Int' #}
@@ -510,14 +511,14 @@
        {} -> `()' supressWarningAboutRes #}
 {# fun Fl_handle as handle'
        { `Int',id `Ptr ()' } -> `Int' #}
-handle :: (Parent a Window) =>  Event -> Ref a -> IO Int
+handle :: (Parent a Window) =>  Event -> Ref a -> IO (Either UnknownEvent ())
 handle e wp =
-    withRef wp (handle' (cFromEnum e))
+    withRef wp (handle' (cFromEnum e)) >>= return . successOrUnknownEvent
 {# fun Fl_handle_ as handle_'
        { `Int',id `Ptr ()' } -> `Int' #}
-handle_ :: (Parent a Window) =>  Event -> Ref a -> IO Int
+handle_ :: (Parent a Window) =>  Event -> Ref a -> IO (Either UnknownEvent ())
 handle_ e wp =
-    withRef wp (handle_' (cFromEnum e))
+    withRef wp (handle_' (cFromEnum e)) >>= return . successOrUnknownEvent
 {# fun Fl_belowmouse as belowmouse
        {  } -> `Maybe (Ref Widget)' unsafeToMaybeRef #}
 {# fun Fl_set_belowmouse as setBelowmouse'
@@ -562,7 +563,8 @@
        { id `Ptr (FunPtr EventDispatchPrim)' } -> `()' supressWarningAboutRes #}
 {# fun Fl_event_dispatch as eventDispatch'
        {  } -> `FunPtr EventDispatchPrim' id #}
-eventDispatch :: (Parent a Widget) => IO (Event -> Ref a -> IO (Int))
+eventDispatch :: (Parent a Widget) =>
+   IO (Event -> Ref a -> IO (Either UnknownEvent ()))
 eventDispatch =
     do
       funPtr <- eventDispatch'
@@ -573,11 +575,13 @@
                          let eventNum = fromIntegral (fromEnum e)
                              fun = unwrapEventDispatchPrim funPtr
                          in fun eventNum (castPtr ptr) >>=
-                            return . fromIntegral
+                            return . successOrUnknownEvent . fromIntegral
                     )
              )
 
-setEventDispatch :: (Parent a Widget) => (Event -> Ref a -> IO Int) -> IO ()
+setEventDispatch ::
+    (Parent a Widget) =>
+    (Event -> Ref a -> IO (Either UnknownEvent ())) -> IO ()
 setEventDispatch ed = do
     do
       let toPrim = (\e ptr ->
@@ -585,7 +589,9 @@
                       in do
                       obj <- toRef ptr
                       result <- ed eventEnum obj
-                      return $ fromIntegral result
+                      case result of
+                        Left _ -> return 0
+                        _ -> return 1
                     )
       callbackPtr <-  wrapEventDispatchPrim toPrim
       ptrToCallbackPtr <- new callbackPtr
@@ -893,10 +899,10 @@
       {  } -> `Bool' toBool #}
 release :: IO ()
 release = {#call Fl_release as fl_release #}
-setVisibleFocus :: Int -> IO ()
-setVisibleFocus = {#call Fl_set_visible_focus as fl_set_visible_focus #} . fromIntegral
-visibleFocus :: IO Int
-visibleFocus = {#call Fl_visible_focus as fl_visible_focus #} >>= return . fromIntegral
+setVisibleFocus :: Bool -> IO ()
+setVisibleFocus = {#call Fl_set_visible_focus as fl_set_visible_focus #} . cFromBool
+visibleFocus :: IO Bool
+visibleFocus = {#call Fl_visible_focus as fl_visible_focus #} >>= return . cToBool
 setDndTextOps :: Bool -> IO ()
 setDndTextOps =  {#call Fl_set_dnd_text_ops as fl_set_dnd_text_ops #} . fromBool
 dndTextOps :: IO Option
diff --git a/src/Graphics/UI/FLTK/LowLevel/Fl_Types.chs b/src/Graphics/UI/FLTK/LowLevel/Fl_Types.chs
--- a/src/Graphics/UI/FLTK/LowLevel/Fl_Types.chs
+++ b/src/Graphics/UI/FLTK/LowLevel/Fl_Types.chs
@@ -342,6 +342,12 @@
 newtype PixmapHs = PixmapHs [T.Text] deriving Show
 data BitmapHs = BitmapHs B.ByteString Size deriving Show
 data Clipboard = InternalClipboard | SharedClipboard deriving Show
+data OutOfRangeOrNotSubmenu = OutOfRangeOrNotSubmenu deriving Show
+successOrOutOfRangeOrNotSubmenu :: Int -> Either OutOfRangeOrNotSubmenu ()
+successOrOutOfRangeOrNotSubmenu status = if (status == (-1)) then Left OutOfRangeOrNotSubmenu else Right ()
+data AwakeRingFull = AwakeRingFull deriving Show
+successOrAwakeRingFull :: Int -> Either AwakeRingFull ()
+successOrAwakeRingFull status = if (status == (-1)) then Left AwakeRingFull else Right ()
 data UnknownEvent = UnknownEvent deriving Show
 successOrUnknownEvent :: Int -> Either UnknownEvent ()
 successOrUnknownEvent status = if (status == 0) then Left UnknownEvent else Right ()
diff --git a/src/Graphics/UI/FLTK/LowLevel/Input.chs b/src/Graphics/UI/FLTK/LowLevel/Input.chs
--- a/src/Graphics/UI/FLTK/LowLevel/Input.chs
+++ b/src/Graphics/UI/FLTK/LowLevel/Input.chs
@@ -99,7 +99,7 @@
       input
       (\p -> do
           t <- getInputType input
-          case (toEnum (fromIntegral t)) of
+          case t of
            FlSecretInput -> secretInputHandle' p (fromIntegral . fromEnum $ event)
            _             -> inputHandle' p (fromIntegral . fromEnum $ event)
       )
@@ -222,11 +222,11 @@
 instance (impl ~ (Color ->  IO ())) => Op (SetCursorColor ()) Input orig impl where
   runOp _ _ input n = withRef input $ \inputPtr -> setCursorColor' inputPtr n
 {# fun Fl_Input_input_type as inputType' { id `Ptr ()' } -> `Int' #}
-instance (impl ~ ( IO (Int))) => Op (GetInputType ()) Input orig impl where
-  runOp _ _ input = withRef input $ \inputPtr -> inputType' inputPtr
+instance (impl ~ ( IO (FlInputType))) => Op (GetInputType ()) Input orig impl where
+  runOp _ _ input = withRef input $ \inputPtr -> inputType' inputPtr >>= return . toEnum . fromIntegral
 {# fun Fl_Input_set_input_type as setInputType' { id `Ptr ()',`Int' } -> `()' #}
-instance (impl ~ (Int ->  IO ())) => Op (SetInputType ()) Input orig impl where
-  runOp _ _ input t = withRef input $ \inputPtr -> setInputType' inputPtr t
+instance (impl ~ (FlInputType ->  IO ())) => Op (SetInputType ()) Input orig impl where
+  runOp _ _ input t = withRef input $ \inputPtr -> setInputType' inputPtr (fromIntegral (fromEnum t))
 {# fun Fl_Input_readonly as readonly' { id `Ptr ()' } -> `Int' #}
 instance (impl ~ ( IO (Int))) => Op (GetReadonly ()) Input orig impl where
   runOp _ _ input = withRef input $ \inputPtr -> readonly' inputPtr
@@ -234,17 +234,17 @@
 instance (impl ~ (Int ->  IO ())) => Op (SetReadonly ()) Input orig impl where
   runOp _ _ input b = withRef input $ \inputPtr -> setReadonly' inputPtr b
 {# fun Fl_Input_wrap as wrap' { id `Ptr ()' } -> `Int' #}
-instance (impl ~ ( IO (Int))) => Op (GetWrap ()) Input orig impl where
-  runOp _ _ input = withRef input $ \inputPtr -> wrap' inputPtr
-{# fun Fl_Input_set_wrap as setWrap' { id `Ptr ()',`Int' } -> `()' #}
-instance (impl ~ (Int ->  IO ())) => Op (SetWrap ()) Input orig impl where
-  runOp _ _ input b = withRef input $ \inputPtr -> setWrap' inputPtr b
-{# fun Fl_Input_tab_nav as tabNav' { id `Ptr ()',`Int' } -> `()' #}
-instance (impl ~ (Int ->  IO ())) => Op (GetTabNav ()) Input orig impl where
-  runOp _ _ input val = withRef input $ \inputPtr -> tabNav' inputPtr val
-{# fun Fl_Input_set_tab_nav as setTabNav' { id `Ptr ()' } -> `Int' #}
-instance (impl ~ ( IO (Int))) => Op (SetTabNav ()) Input orig impl where
-  runOp _ _ input = withRef input $ \inputPtr -> setTabNav' inputPtr
+instance (impl ~ ( IO (Bool))) => Op (GetWrap ()) Input orig impl where
+  runOp _ _ input = withRef input $ \inputPtr -> wrap' inputPtr >>= return . cToBool
+{# fun Fl_Input_set_wrap as setWrap' { id `Ptr ()', `Int' } -> `()' #}
+instance (impl ~ (Bool ->  IO ())) => Op (SetWrap ()) Input orig impl where
+  runOp _ _ input b = withRef input $ \inputPtr -> setWrap' inputPtr (cFromBool b)
+{# fun Fl_Input_set_tab_nav as setTabNav' { id `Ptr ()', `Int'} -> `()' #}
+instance (impl ~ (Bool ->  IO ())) => Op (SetTabNav ()) Input orig impl where
+  runOp _ _ input val = withRef input $ \inputPtr -> setTabNav' inputPtr (cFromBool val)
+{# fun Fl_Input_tab_nav as tabNav' { id `Ptr ()' } -> `Int' #}
+instance (impl ~ ( IO (Bool))) => Op (GetTabNav ()) Input orig impl where
+  runOp _ _ input = withRef input $ \inputPtr -> tabNav' inputPtr >>= return . cToBool
 {# fun Fl_Input_draw as draw'' { id `Ptr ()' } -> `()' #}
 instance (impl ~ (  IO ())) => Op (Draw ()) Input orig impl where
   runOp _ _ input = withRef input $ \inputPtr -> draw'' inputPtr
@@ -298,7 +298,7 @@
 --
 -- getCursorColor :: 'Ref' 'Input' -> 'IO' ('Color')
 --
--- getInputType :: 'Ref' 'Input' -> 'IO' ('Int')
+-- getInputType :: 'Ref' 'Input' -> 'IO' ('FlInputType')
 --
 -- getMark :: 'Ref' 'Input' -> 'IO' ('Int')
 --
@@ -312,7 +312,7 @@
 --
 -- getSize :: 'Ref' 'Input' -> 'IO' ('Int')
 --
--- getTabNav :: 'Ref' 'Input' -> 'Int' -> 'IO' ()
+-- getTabNav :: 'Ref' 'Input' -> 'IO' ('Bool')
 --
 -- getTextcolor :: 'Ref' 'Input' -> 'IO' ('Color')
 --
@@ -322,7 +322,7 @@
 --
 -- getValue :: 'Ref' 'Input' -> 'IO' 'T.Text'
 --
--- getWrap :: 'Ref' 'Input' -> 'IO' ('Int')
+-- getWrap :: 'Ref' 'Input' -> 'IO' ('Bool')
 --
 -- handle :: 'Ref' 'Input' -> 'Event' -> 'IO' ('Either' 'UnknownEvent' ())
 --
@@ -346,7 +346,7 @@
 --
 -- setCursorColor :: 'Ref' 'Input' -> 'Color' -> 'IO' ()
 --
--- setInputType :: 'Ref' 'Input' -> 'Int' -> 'IO' ()
+-- setInputType :: 'Ref' 'Input' -> 'FlInputType' -> 'IO' ()
 --
 -- setMark :: 'Ref' 'Input' -> 'Int' -> 'IO' ('Either' 'NoChange' ())
 --
@@ -360,7 +360,7 @@
 --
 -- setSize :: 'Ref' 'Input' -> 'Size' -> 'IO' ()
 --
--- setTabNav :: 'Ref' 'Input' -> 'IO' ('Int')
+-- setTabNav :: 'Ref' 'Input' -> 'Bool' -> 'IO' ()
 --
 -- setTextcolor :: 'Ref' 'Input' -> 'Color' -> 'IO' ()
 --
@@ -372,7 +372,7 @@
 --
 -- setValue :: 'Ref' 'Input' -> 'T.Text' -> 'Maybe' 'Int' -> 'IO' ('Int')
 --
--- setWrap :: 'Ref' 'Input' -> 'Int' -> 'IO' ()
+-- setWrap :: 'Ref' 'Input' -> 'Bool' -> 'IO' ()
 --
 -- showWidget :: 'Ref' 'Input' -> 'IO' ()
 --
diff --git a/src/Graphics/UI/FLTK/LowLevel/OverlayWindow.chs b/src/Graphics/UI/FLTK/LowLevel/OverlayWindow.chs
--- a/src/Graphics/UI/FLTK/LowLevel/OverlayWindow.chs
+++ b/src/Graphics/UI/FLTK/LowLevel/OverlayWindow.chs
@@ -54,8 +54,8 @@
 instance (impl ~ ( IO ())) => Op (Hide ()) OverlayWindow orig impl where
   runOp _ _ window = withRef window $ \windowPtr -> hide' windowPtr
 {# fun Fl_Overlay_Window_can_do_overlay as canDoOverlay' { id `Ptr ()' } -> `Int' #}
-instance (impl ~ ( IO (Int))) => Op (CanDoOverlay ()) OverlayWindow orig impl where
-  runOp _ _ win = withRef win $ \winPtr -> canDoOverlay' winPtr
+instance (impl ~ ( IO (Bool))) => Op (CanDoOverlay ()) OverlayWindow orig impl where
+  runOp _ _ win = withRef win $ \winPtr -> canDoOverlay' winPtr >>= return . cToBool
 {# fun Fl_Overlay_Window_redraw_overlay as redrawOverlay' { id `Ptr ()' } -> `()' #}
 instance (impl ~ ( IO ())) => Op (RedrawOverlay ()) OverlayWindow orig impl where
   runOp _ _ win = withRef win $ \winPtr -> redrawOverlay' winPtr
@@ -63,7 +63,7 @@
 -- $functions
 -- @
 --
--- canDoOverlay :: 'Ref' 'OverlayWindow' -> 'IO' 'Int'
+-- canDoOverlay :: 'Ref' 'OverlayWindow' -> 'IO' ('Bool')
 --
 -- destroy :: 'Ref' 'OverlayWindow' -> 'IO' ()
 --
diff --git a/src/Graphics/UI/FLTK/LowLevel/SysMenuBar.chs b/src/Graphics/UI/FLTK/LowLevel/SysMenuBar.chs
--- a/src/Graphics/UI/FLTK/LowLevel/SysMenuBar.chs
+++ b/src/Graphics/UI/FLTK/LowLevel/SysMenuBar.chs
@@ -69,8 +69,8 @@
 instance (impl ~ ( IO ())) => Op (Clear ()) SysMenuBar orig impl where
   runOp _ _ menu_ = withRef menu_ $ \menu_Ptr -> clear' menu_Ptr
 {# fun Fl_Sys_Menu_Bar_clear_submenu as clearSubmenu' { id `Ptr ()',`Int' } -> `Int' #}
-instance (impl ~ (Int ->  IO (Int))) => Op (ClearSubmenu ()) SysMenuBar orig impl where
-  runOp _ _ menu_ index' = withRef menu_ $ \menu_Ptr -> clearSubmenu' menu_Ptr index'
+instance (impl ~ (Int ->  IO (Either OutOfRangeOrNotSubmenu ()))) => Op (ClearSubmenu ()) SysMenuBar orig impl where
+  runOp _ _ menu_ index' = withRef menu_ $ \menu_Ptr -> clearSubmenu' menu_Ptr index' >>= return . successOrOutOfRangeOrNotSubmenu
 {# fun Fl_Sys_Menu_Bar_shortcut as shortcut' { id `Ptr ()',`Int',id `CInt' } -> `()' #}
 instance (impl ~ (Int -> ShortcutKeySequence ->  IO ())) => Op (SetShortcut ()) SysMenuBar orig impl where
   runOp _ _ menu_ index' (ShortcutKeySequence modifiers char) =
@@ -149,7 +149,7 @@
 --
 -- clear :: 'Ref' 'SysMenuBar' -> 'IO' ()
 --
--- clearSubmenu :: 'Ref' 'SysMenuBar' -> 'Int' -> 'IO' ('Int')
+-- clearSubmenu :: 'Ref' 'SysMenuBar' -> 'Int' -> 'IO' ('Either' 'OutOfRangeOrNotSubmenu' ())
 --
 -- destroy :: 'Ref' 'SysMenuBar' -> 'IO' ()
 --
@@ -160,8 +160,6 @@
 -- getMode :: 'Ref' 'SysMenuBar' -> 'Int' -> 'IO' ('Maybe' 'MenuItemFlags')
 --
 -- global :: 'Ref' 'SysMenuBar' -> 'IO' ()
---
--- handle :: 'Ref' 'SysMenuBar' -> 'Event' -> 'IO' ('Either' 'UnknownEvent' ())
 --
 -- handle :: 'Ref' 'SysMenuBar' -> 'Event' -> 'IO' ('Either' 'UnknownEvent' ())
 --
diff --git a/src/Graphics/UI/FLTK/LowLevel/Table.chs b/src/Graphics/UI/FLTK/LowLevel/Table.chs
--- a/src/Graphics/UI/FLTK/LowLevel/Table.chs
+++ b/src/Graphics/UI/FLTK/LowLevel/Table.chs
@@ -275,8 +275,8 @@
 instance (impl ~ ( Int -> Int -> Int -> Int ->  IO ())) => Op (SetSelection ()) Table orig impl where
   runOp _ _ table row_top col_left row_bot col_right = withRef table $ \tablePtr -> setSelection' tablePtr row_top col_left row_bot col_right
 {# fun Fl_Table_move_cursor as moveCursor' { id `Ptr ()',`Int',`Int' } -> `Int' #}
-instance (impl ~ ( TableCoordinate ->  IO (Int))) => Op (MoveCursor ()) Table orig impl where
-  runOp _ _ table (TableCoordinate (Row r) (Column c)) = withRef table $ \tablePtr -> moveCursor' tablePtr r c
+instance (impl ~ ( TableCoordinate ->  IO (Either NoChange ()))) => Op (MoveCursor ()) Table orig impl where
+  runOp _ _ table (TableCoordinate (Row r) (Column c)) = withRef table $ \tablePtr -> moveCursor' tablePtr r c >>= return . successOrNoChange
 {# fun Fl_Table_init_sizes as initSizes' { id `Ptr ()' } -> `()' #}
 instance (impl ~ (  IO ())) => Op (InitSizes ()) Table orig impl where
   runOp _ _ table = withRef table $ \tablePtr -> initSizes' tablePtr
@@ -337,7 +337,7 @@
 instance (impl ~ (  IO ())) => Op (Draw ()) Table orig impl where
   runOp _ _ table = withRef table $ \tablePtr -> draw' tablePtr
 {# fun Fl_Table_handle as handle' { id `Ptr ()', cFromEnum `Event' } -> `Int' #}
-instance (impl ~ ( Event ->  IO(Either UnknownEvent ()))) => Op (Handle ()) Table orig impl where
+instance (impl ~ ( Event ->  IO( Either UnknownEvent ()))) => Op (Handle ()) Table orig impl where
   runOp _ _ table event = withRef table $ \tablePtr -> handle' tablePtr event >>= return  . successOrUnknownEvent
 {# fun Fl_Table_resize_super as resizeSuper' { id `Ptr ()',`Int',`Int',`Int',`Int' } -> `()' #}
 instance (impl ~ ( Rectangle ->  IO ())) => Op (ResizeSuper ()) Table orig impl where
@@ -447,7 +447,7 @@
 --
 -- getVisibleCells :: 'Ref' 'Table' -> 'IO' ('TableCoordinate,TableCoordinate')
 --
--- handle :: 'Ref' 'Table' -> 'Event' -> 'IO' ('Int')
+-- handle :: 'Ref' 'Table' -> 'Event' -> 'IO' ( 'Either' 'UnknownEvent' () )
 --
 -- hide :: 'Ref' 'Table' -> 'IO' ()
 --
@@ -463,7 +463,7 @@
 --
 -- isSelected :: 'Ref' 'Table' -> 'TableCoordinate' -> 'IO' 'Bool'
 --
--- moveCursor :: 'Ref' 'Table' -> 'TableCoordinate' -> 'IO' ('Int')
+-- moveCursor :: 'Ref' 'Table' -> 'TableCoordinate' -> 'IO' ('Either' 'NoChange' ())
 --
 -- resize :: 'Ref' 'Table' -> 'Rectangle' -> 'IO' ()
 --
diff --git a/src/Graphics/UI/FLTK/LowLevel/Tree.chs b/src/Graphics/UI/FLTK/LowLevel/Tree.chs
--- a/src/Graphics/UI/FLTK/LowLevel/Tree.chs
+++ b/src/Graphics/UI/FLTK/LowLevel/Tree.chs
@@ -212,12 +212,12 @@
 {# fun Fl_Tree_select_with_item_docallback as selectWithItemDocallback' { id `Ptr ()',id `Ptr ()',cFromBool `Bool' } -> `Int' #}
 {# fun Fl_Tree_select_with_path as selectWithPath' { id `Ptr ()',unsafeToCString `T.Text' } -> `Int' #}
 {# fun Fl_Tree_select_with_path_docallback as selectWithPathDocallback' { id `Ptr ()',unsafeToCString `T.Text',cFromBool `Bool' } -> `Int' #}
-instance (impl ~ (TreeItemLocator  ->  IO (Int)) ) => Op (Select ()) Tree orig impl where
+instance (impl ~ (TreeItemLocator  ->  IO (Either NoChange ())) ) => Op (Select ()) Tree orig impl where
   runOp _ _ tree locator' =
     withRef tree $ \treePtr ->
     case locator' of
-      TreeItemPointerLocator (TreeItemPointer r') -> withRef r' $ \r'Ptr -> selectWithItem' treePtr r'Ptr
-      TreeItemNameLocator (TreeItemName n') -> selectWithPath' treePtr n'
+      TreeItemPointerLocator (TreeItemPointer r') -> withRef r' $ \r'Ptr -> selectWithItem' treePtr r'Ptr >>= return . successOrNoChange
+      TreeItemNameLocator (TreeItemName n') -> selectWithPath' treePtr n' >>= return . successOrNoChange
 instance  (impl ~ (TreeItemLocator -> Bool -> IO ())) => Op (SelectAndCallback ()) Tree orig impl where
   runOp _ _ tree_item locator' docallback' =
     withRef tree_item $ \tree_itemPtr ->
@@ -234,12 +234,12 @@
 {# fun Fl_Tree_deselect_with_item_docallback as deselectWithItemDocallback' { id `Ptr ()',id `Ptr ()',cFromBool `Bool' } -> `Int' #}
 {# fun Fl_Tree_deselect_with_path as deselectWithPath' { id `Ptr ()', unsafeToCString `T.Text'} -> `Int' #}
 {# fun Fl_Tree_deselect_with_path_docallback as deselectWithPathDocallback' { id `Ptr ()',unsafeToCString `T.Text',cFromBool `Bool' } -> `Int' #}
-instance (impl ~ (TreeItemLocator  ->  IO (Int)) ) => Op (Deselect ()) Tree orig impl where
+instance (impl ~ (TreeItemLocator  ->  IO (Either NoChange ())) ) => Op (Deselect ()) Tree orig impl where
   runOp _ _ tree locator' =
     withRef tree $ \treePtr ->
     case locator' of
-      TreeItemPointerLocator (TreeItemPointer r') -> withRef r' $ \r'Ptr -> deselectWithItem' treePtr r'Ptr
-      TreeItemNameLocator (TreeItemName n') -> deselectWithPath' treePtr n'
+      TreeItemPointerLocator (TreeItemPointer r') -> withRef r' $ \r'Ptr -> deselectWithItem' treePtr r'Ptr >>= return . successOrNoChange
+      TreeItemNameLocator (TreeItemName n') -> deselectWithPath' treePtr n' >>= return . successOrNoChange
 instance  (impl ~ (TreeItemLocator -> Bool -> IO ())) => Op (DeselectAndCallback ()) Tree orig impl where
   runOp _ _ tree_item locator' docallback' =
     withRef tree_item $ \tree_itemPtr ->
diff --git a/src/Graphics/UI/FLTK/LowLevel/Widget.chs b/src/Graphics/UI/FLTK/LowLevel/Widget.chs
--- a/src/Graphics/UI/FLTK/LowLevel/Widget.chs
+++ b/src/Graphics/UI/FLTK/LowLevel/Widget.chs
@@ -390,11 +390,13 @@
 instance (impl ~ (IO (Bool))) => Op (GetVisibleFocus ()) Widget orig impl where
   runOp _ _ widget = withRef widget $ \widgetPtr -> visibleFocus' widgetPtr
 {# fun Fl_Widget_contains as contains' { id `Ptr ()',id `Ptr ()' } -> `Int' #}
-instance (Parent a Widget, impl ~  (Ref a ->  IO Int)) => Op (Contains ()) Widget orig impl where
-  runOp _ _ widget otherWidget = withRef widget $ \widgetPtr -> withRef otherWidget $ \otherWidgetPtr -> contains' widgetPtr otherWidgetPtr
+instance (Parent a Widget, impl ~  (Ref a ->  IO Bool)) => Op (Contains ()) Widget orig impl where
+  runOp _ _ widget otherWidget = withRef widget $ \widgetPtr -> withRef otherWidget $ \otherWidgetPtr ->
+    contains' widgetPtr otherWidgetPtr >>= return . cToBool
 {# fun Fl_Widget_inside as inside' { id `Ptr ()',id `Ptr ()' } -> `Int' #}
-instance (Parent a Widget, impl ~ (Ref a -> IO (Int))) => Op (Inside ()) Widget orig impl where
-  runOp _ _ widget otherWidget = withRef widget $ \widgetPtr -> withRef otherWidget $ \otherWidgetPtr -> inside' widgetPtr otherWidgetPtr
+instance (Parent a Widget, impl ~ (Ref a -> IO (Bool))) => Op (Inside ()) Widget orig impl where
+  runOp _ _ widget otherWidget = withRef widget $ \widgetPtr -> withRef otherWidget $ \otherWidgetPtr ->
+    inside' widgetPtr otherWidgetPtr >>= return . cToBool
 {# fun Fl_Widget_redraw as redraw' { id `Ptr ()' } -> `()' supressWarningAboutRes #}
 instance (impl ~ (IO ())) => Op (Redraw ()) Widget orig impl where
   runOp _ _ widget = withRef widget $ \widgetPtr -> redraw' widgetPtr
@@ -503,7 +505,7 @@
 --
 -- clearVisibleFocus :: 'Ref' 'Widget' -> 'IO' ()
 --
--- contains:: ('Parent' a 'Widget') => 'Ref' 'Widget' -> 'Ref' a -> 'IO' 'Int'
+-- contains:: ('Parent' a 'Widget') => 'Ref' 'Widget' -> 'Ref' a -> 'IO' 'Bool'
 --
 -- copyLabel :: 'Ref' 'Widget' -> 'T.Text' -> 'IO' ()
 --
@@ -589,7 +591,7 @@
 --
 -- hideSuper :: 'Ref' 'Widget' -> 'IO' ()
 --
--- inside:: ('Parent' a 'Widget') => 'Ref' 'Widget' -> 'Ref' a -> 'IO' ('Int')
+-- inside:: ('Parent' a 'Widget') => 'Ref' 'Widget' -> 'Ref' a -> 'IO' ('Bool')
 --
 -- measureLabel :: 'Ref' 'Widget' -> 'IO' ('Size')
 --