Yeah, what a shame for our several months old last stable release that it
doesn't support some extension that's apparently so new that even X.org 6.9.0
doesn't include it. I at least cannot find it anywhere, doc/hardcopy/Xext
describes only XShape 1.0 and I don't see anything in the libXext code either.

Where can one find anything about this?

do "xdpyinfo -ext SHAPE" to see your version.
no, that spec isn't totally new and is supported by at least Xorg7.0 (and therefore 6.9 too), and metacity 2.8.6, which is of gnome 2.8(!). 
also consider that i was joking when i said that it would be a shame for KDE. everyone knows that KDE doesn't have to shame for anything :)

It is new, the newest X.org version at the time of 3.5.0 release was 6.8, which
has only XShape 1.0. And this still doesn't answer the question of any docs for
it - I guess it will be again something along the lines of "ask your favourite
X developer" :-/.

Keith updated the XShape specification to 1.1 just four days ago. ;-)

See http://webcvs.freedesktop.org/xorg/doc/xorg-docs/specs/Xext/shape.ms?rev=1.4&view=log.

ok you're soo right. it's too new. just would be happy if kwin supports it...
thx to all

SVN commit 571711 by lunakl:

Support for input shape from XShape1.1.
FEATURE: 122425



 M  +23 -10    client.cpp  
 M  +2 -4      geometry.cpp  
 M  +2 -6      manage.cpp  
 M  +9 -4      utils.cpp  
 M  +4 -2      utils.h  


--- branches/KDE/3.5/kdebase/kwin/client.cpp #571710:571711
@@ -458,24 +458,37 @@
 
 void Client::updateShape()
     {
-    setShapable(TRUE);
+    // workaround for #19644 - shaped windows shouldn't have decoration
+    if( shape() && !noBorder()) 
+        {
+        noborder = true;
+        updateDecoration( true );
+        }
     if ( shape() )
-    {
+        {
         XShapeCombineShape(qt_xdisplay(), frameId(), ShapeBounding,
                            clientPos().x(), clientPos().y(),
                            window(), ShapeBounding, ShapeSet);
-    }
+        setShapable(TRUE);
+        }
     else
-    {
+        {
         XShapeCombineMask( qt_xdisplay(), frameId(), ShapeBounding, 0, 0,
                            None, ShapeSet);
-    }
-    // workaround for #19644 - shaped windows shouldn't have decoration
-    if( shape() && !noBorder()) 
-        {
-        noborder = true;
-        updateDecoration( true );
         }
+    if( Shape::major() > 1 || Shape::minor() >= 1 ) // has input shape support
+        { // there appears to be no way to find out if a window has input
+          // shape set or not, so always set propagate the input shape
+          // (it's the same like the bounding shape by default)
+        XShapeCombineMask( qt_xdisplay(), frameId(), ShapeInput, 0, 0,
+                           None, ShapeSet );
+        XShapeCombineShape( qt_xdisplay(), frameId(), ShapeInput,
+                           clientPos().x(), clientPos().y(),
+                           window(), ShapeBounding, ShapeSubtract );
+        XShapeCombineShape( qt_xdisplay(), frameId(), ShapeInput,
+                           clientPos().x(), clientPos().y(),
+                           window(), ShapeInput, ShapeUnion );
+        }
     }
 
 void Client::setMask( const QRegion& reg, int mode )
--- branches/KDE/3.5/kdebase/kwin/geometry.cpp #571710:571711
@@ -1709,8 +1709,7 @@
             cs.width(), cs.height());
         XMoveResizeWindow( qt_xdisplay(), window(), 0, 0, cs.width(), cs.height());
         }
-    if( shape())
-        updateShape();
+    updateShape();
     // SELI TODO won't this be too expensive?
     updateWorkareaDiffs();
     sendSyntheticConfigureNotify();
@@ -1764,8 +1763,7 @@
             cs.width(), cs.height());
         XMoveResizeWindow( qt_xdisplay(), window(), 0, 0, cs.width(), cs.height());
         }
-    if( shape())
-        updateShape();
+    updateShape();
     updateWorkareaDiffs();
     sendSyntheticConfigureNotify();
     updateWindowRules();
--- branches/KDE/3.5/kdebase/kwin/manage.cpp #571710:571711
@@ -316,12 +316,8 @@
         keepInArea( area, partial_keep_in_area );
 
     XShapeSelectInput( qt_xdisplay(), window(), ShapeNotifyMask );
-    if ( (is_shape = Shape::hasShape( window())) ) 
-        {
-        updateShape();
-        }
-//    else
-//	setShapable(FALSE);
+    is_shape = Shape::hasShape( window());
+    updateShape();
 	
     //CT extra check for stupid jdk 1.3.1. But should make sense in general
     // if client has initial state set to Iconic and is transient with a parent
--- branches/KDE/3.5/kdebase/kwin/utils.cpp #571710:571711
@@ -44,7 +44,7 @@
 // used to store the return values of
 // XShapeQueryExtension.
 // Necessary since shaped window are an extension to X
-int Shape::kwin_has_shape = 0;
+int Shape::kwin_shape_version = 0;
 int Shape::kwin_shape_event = 0;
 
 // does the window w  need a shape combine mask around it?
@@ -53,7 +53,7 @@
     int xws, yws, xbs, ybs;
     unsigned int wws, hws, wbs, hbs;
     int boundingShaped = 0, clipShaped = 0;
-    if (!kwin_has_shape)
+    if (!available())
         return FALSE;
     XShapeQueryExtents(qt_xdisplay(), w,
                        &boundingShaped, &xws, &yws, &wws, &hws,
@@ -68,9 +68,14 @@
 
 void Shape::init()
     {
+    kwin_shape_version = 0;
     int dummy;
-    kwin_has_shape =
-      XShapeQueryExtension(qt_xdisplay(), &kwin_shape_event, &dummy);
+    if( !XShapeQueryExtension(qt_xdisplay(), &kwin_shape_event, &dummy))
+        return;
+    int major, minor;
+    if( !XShapeQueryVersion( qt_xdisplay(), &major, &minor ))
+        return;
+    kwin_shape_version = major * 16 + minor;
     }
 
 void Motif::readFlags( WId w, bool& noborder, bool& resize, bool& move,
--- branches/KDE/3.5/kdebase/kwin/utils.h #571710:571711
@@ -111,12 +111,14 @@
 class Shape 
     {
     public:
-        static bool available() { return kwin_has_shape; }
+        static bool available() { return kwin_shape_version > 0; }
+        static int major() { return kwin_shape_version / 16; }
+        static int minor() { return kwin_shape_version % 16; }
         static bool hasShape( WId w);
         static int shapeEvent();
         static void init();
     private:
-        static int kwin_has_shape;
+        static int kwin_shape_version; // as 16*major+minor
         static int kwin_shape_event;
     };