add SimpleStacking module to make Combo and Tabbed work together.

WARNING! This change will break existing Tabbed configurations.  The
problem is that there is no way within a Layout's "doLayout" to safely
modify the layout itself.  This makes LayoutHooks fragile, and more to the
point, makes SimpleStacking fragile, so we can't safely define a

tabbed' = simpleStacking . tabbed

A workaround would have been to duplicate the tabbed code, but I'd rather
leave the ugliness and get this fixed.

Combo.hs

@@ -27,10 +27,11 @@ import Operations ( UnDoLayout(UnDoLayout) )
 -- To use this layout write, in your Config.hs:
 -- 
 -- > import XMonadContrib.Combo 
+-- > import XMonadContrib.SimpleStacking
 -- 
 -- and add something like
 -- 
--- > combo [(full,1),(tabbed shrinkText,1)] (twoPane 0.03 0.5)
+-- > simpleStacking $ combo [(full,1),(tabbed shrinkText,1)] (twoPane 0.03 0.5)
 --
 -- to your defaultLayouts.
 

MetaModule.hs

@@ -42,6 +42,7 @@ import XMonadContrib.NamedWindows ()
 import XMonadContrib.NoBorders ()
 import XMonadContrib.RotView ()
 import XMonadContrib.SimpleDate ()
+import XMonadContrib.SimpleStacking ()
 import XMonadContrib.Spiral ()
 import XMonadContrib.Square ()
 import XMonadContrib.Submap ()

SimpleStacking.hs

@@ -0,0 +1,50 @@
+{-# OPTIONS -fglasgow-exts #-}
+-----------------------------------------------------------------------------
+-- |
+-- Module      :  XMonadContrib.SimpleStacking
+-- Copyright   :  (c) David Roundy <droundy@darcs.net>
+-- License     :  BSD-style (see LICENSE)
+-- 
+-- Maintainer  :  David Roundy <droundy@darcs.net>
+-- Stability   :  unstable
+-- Portability :  unportable
+--
+-- A module to be used to obtain a simple "memory" of stacking order.
+--
+-----------------------------------------------------------------------------
+
+module XMonadContrib.SimpleStacking (
+                                     -- * Usage
+                                     -- $usage 
+                                     simpleStacking
+                                    ) where
+
+import Control.Monad.State ( modify )
+import qualified Data.Map as M
+import Data.Maybe ( catMaybes )
+
+import Data.List ( nub, lookup )
+import StackSet ( focus, tag, workspace, current, integrate )
+import Graphics.X11.Xlib ( Window )
+
+import XMonad
+
+-- $usage
+-- You can use this module for 
+-- See, for instance, "XMonadContrib.Tabbed"
+
+simpleStacking :: Layout Window -> Layout Window
+simpleStacking = simpleStacking' []
+
+simpleStacking' :: [Window] -> Layout Window -> Layout Window
+simpleStacking' st l = l { doLayout = dl
+                         , modifyLayout = \m -> fmap (simpleStacking' st) `fmap` modifyLayout l m }
+    where dl r s = do modify $ \ state ->
+                          state { layouts = M.adjust
+                                            (\(_,ss)->(simpleStacking'
+                                                       (focus s:filter (`elem` integrate s) st) l,ss))
+                                            (tag.workspace.current.windowset $ state)
+                                            (layouts state) }
+                      lo <- doLayout l r s
+                      let m = map (\ (w,rr) -> (w,(w,rr))) lo
+                      return $ catMaybes $ map ((flip lookup) m) $ nub (focus s : st ++ map fst lo)

Tabbed.hs

@@ -34,18 +34,18 @@ import XMonadContrib.NamedWindows
 -- You can use this module with the following in your configuration file:
 --
 -- > import XMonadContrib.Tabbed
+-- > import XMonadContrib.SimpleStacking
 --
 -- > defaultLayouts :: [Layout]
--- > defaultLayouts = [ tabbed shrinkText
+-- > defaultLayouts = [ simpleStacking $ tabbed shrinkText
 -- >                 , ... ]
 
-
 tabbed :: Shrinker -> Layout Window
 tabbed shrinkT =  Layout { doLayout = dolay shrinkT, modifyLayout = const (return Nothing) }
 
 dolay :: Shrinker -> Rectangle -> W.Stack Window -> X [(Window, Rectangle)]
 dolay _ sc (W.Stack w [] []) = return [(w,sc)]
-dolay shr sc@(Rectangle x y wid _) s@(W.Stack w _ _) = withDisplay $ \dpy ->
+dolay shr sc@(Rectangle x y wid _) s = withDisplay $ \dpy ->
     do activecolor   <- io $ initColor dpy "#BBBBBB"
        inactivecolor <- io $ initColor dpy "#888888"
        textcolor     <- io $ initColor dpy "#000000"
@@ -72,7 +72,7 @@ dolay shr sc@(Rectangle x y wid _) s@(W.Stack w _ _) = withDisplay $ \dpy ->
                          (fromIntegral (wt `div` 2) - fromIntegral (width `div` 2))
                          (fromIntegral ht - fromIntegral (asc `div` 2)) name'
        forM tws maketab
-       return [ (w,shrink sc) ]
+       return $ map (\w -> (w,shrink sc)) ws
 
 type Shrinker = String -> [String]