      */
     public function set postLayoutTransformOffsets(value:TransformOffsets):void
     {
+        // validateMatrix when switching between 2D/3D, works around player bug
+        // see sdk-23421 
+        var was3D:Boolean = is3D;
+
         if (_layoutFeatures == null)
             initAdvancedLayoutFeatures();
         


        if (invalidateLayout)
            invalidateParentSizeAndDisplayList();
    }

    private static var xformPt:Point;

        super.transform.perspectiveProjection = pp;
        if (maintainProjectionCenter)
            invalidateDisplayList(); 
        if (was3D != is3D)
            validateMatrix();
    }
    
    /**
