diff --git a/effects.cpp b/effects.cpp
index c12b9ba93a..d551f8a446 100644
--- a/effects.cpp
+++ b/effects.cpp
@@ -65,6 +65,24 @@ void Effect::paintWorkspace( Workspace*, EffectData& )
 // EffectsHandler
 //****************************************
 
+class MakeHalfTransparent
+    : public Effect
+    {
+    public:
+        virtual void paintWindow( Toplevel* c, EffectData& data );
+    };
+
+void MakeHalfTransparent::paintWindow( Toplevel*, EffectData& data )
+    {
+    data.opacity *= 0.8;
+    }
+
+static MakeHalfTransparent* mht;
+EffectsHandler::EffectsHandler()
+    {
+    mht = new MakeHalfTransparent;
+    }
+
 void EffectsHandler::windowUserMoved( Toplevel* )
     {
     }
@@ -73,8 +91,9 @@ void EffectsHandler::windowUserResized( Toplevel* )
     {
     }
 
-void EffectsHandler::paintWindow( Toplevel*, EffectData& )
+void EffectsHandler::paintWindow( Toplevel* c, EffectData& data )
     {
+    mht->paintWindow( c, data );
     }
 
 void EffectsHandler::paintWorkspace( Workspace*, EffectData& )
diff --git a/effects.h b/effects.h
index 66d8ace60a..775ffe58e8 100644
--- a/effects.h
+++ b/effects.h
@@ -46,6 +46,7 @@ class Effect
 class EffectsHandler
     {
     public:
+        EffectsHandler();
         void windowUserMoved( Toplevel* c );
         void windowUserResized( Toplevel* c );
         void paintWindow( Toplevel* c, EffectData& data );
diff --git a/scene_xrender.cpp b/scene_xrender.cpp
index 99f6088463..5653e15810 100644
--- a/scene_xrender.cpp
+++ b/scene_xrender.cpp
@@ -13,6 +13,7 @@ License. See the file "COPYING" for the exact licensing terms.
 #ifdef HAVE_XRENDER
 
 #include "toplevel.h"
+#include "effects.h"
 
 namespace KWinInternal
 {
@@ -43,6 +44,14 @@ SceneXrender::~SceneXrender()
 
 void SceneXrender::paint( XserverRegion damage )
     {
+#if 0
+    XRectangle r;
+    r.x = 0;
+    r.y = 0;
+    r.width = displayWidth();
+    r.height = displayHeight();
+    XFixesSetRegion( display(), damage, &r, 1 );
+#endif
     // Use the damage region as the clip region for the root window
     XFixesSetPictureClipRegion( display(), front, 0, 0, damage );
     // Client list for clients that are either translucent or have a shadow
@@ -55,6 +64,7 @@ void SceneXrender::paint( XserverRegion damage )
         {
         Toplevel* c = windows[ i ];
         checkWindowData( c );
+        effects->paintWindow( c, window_data[ c ].effect );
         if( isOpaque( c ))
             {
             Picture picture = windowPicture( c );
@@ -91,9 +101,11 @@ void SceneXrender::paint( XserverRegion damage )
             Picture picture = windowPicture( c );
             Picture alpha = windowAlphaMask( c );
             if( picture != None )
+                {
                 // TODO clip also using shape? also above?
                 XRenderComposite( display(), PictOpOver, picture, alpha, buffer, 0, 0, 0, 0,
                     c->x(), c->y(), c->width(), c->height());
+                }
             }
         XFixesDestroyRegion( display(), r );
         }
@@ -110,6 +122,9 @@ void SceneXrender::checkWindowData( Toplevel* c )
         window_data[ c ] = WindowData();
         window_data[ c ].format = XRenderFindVisualFormat( display(), c->visual());
         }
+    WindowData& data = window_data[ c ];
+    data.effect.matrix = Matrix();
+    data.effect.opacity = c->opacity();
     }
 
 void SceneXrender::windowGeometryShapeChanged( Toplevel* c )
@@ -174,7 +189,7 @@ bool SceneXrender::isOpaque( Toplevel* c ) const
     const WindowData& data = window_data[ c ];
     if( data.format->type == PictTypeDirect && data.format->direct.alphaMask )
         return false;
-    if( c->opacity() != 1.0 )
+    if( data.effect.opacity != 1.0 )
         return false;
     return true;
     }
@@ -184,6 +199,12 @@ Picture SceneXrender::windowAlphaMask( Toplevel* c )
     if( isOpaque( c ))
         return None;
     WindowData& data = window_data[ c ];
+    if( data.alpha != None && data.alpha_cached_opacity != data.effect.opacity )
+        {
+        if( data.alpha != None )
+            XRenderFreePicture( display(), data.alpha );
+        data.alpha = None;
+        }
     if( data.alpha != None )
         return data.alpha;
     Pixmap pixmap = XCreatePixmap( display(), rootWindow(), 1, 1, 8 );
@@ -193,7 +214,8 @@ Picture SceneXrender::windowAlphaMask( Toplevel* c )
     data.alpha = XRenderCreatePicture( display(), pixmap, format, CPRepeat, &pa );
     XFreePixmap( display(), pixmap );
     XRenderColor col;
-    col.alpha = int( c->opacity() * 0xffff );
+    col.alpha = int( data.effect.opacity * 0xffff );
+    data.alpha_cached_opacity = data.effect.opacity;
     XRenderFillRectangle( display(), PictOpSrc, data.alpha, &col, 0, 0, 1, 1 );
     return data.alpha;
     }
diff --git a/scene_xrender.h b/scene_xrender.h
index e50b529fed..ec62de0292 100644
--- a/scene_xrender.h
+++ b/scene_xrender.h
@@ -17,10 +17,13 @@ License. See the file "COPYING" for the exact licensing terms.
 #include <X11/extensions/Xrender.h>
 
 #include "scene.h"
+#include "effects.h"
 
 namespace KWinInternal
 {
 
+class Matrix;
+
 class SceneXrender
     : public Scene
     {
@@ -51,7 +54,9 @@ class SceneXrender
             XRenderPictFormat* format;
             XserverRegion saved_clip_region;
             Picture alpha;
+            double alpha_cached_opacity;
             XserverRegion shape;
+            EffectData effect;
             };
         QMap< Toplevel*, WindowData > window_data;
     };