      */
     public function setLayoutMatrix3D(value:Matrix3D, invalidateLayout:Boolean):void
     {
+        // validateMatrix when switching between 2D/3D, works around player bug
+        // see sdk-23421 
+        var was3D:Boolean = is3D;
+
         if (_layoutFeatures == null)
             initAdvancedLayoutFeatures();
         // layout features will internally make a copy of this matrix rather than

        _layoutFeatures.postLayoutTransformOffsets = value;
        if (_layoutFeatures.postLayoutTransformOffsets != null)
            _layoutFeatures.postLayoutTransformOffsets.addEventListener(Event.CHANGE,transformOffsetsChangedHandler);
    }

    /**


        if (invalidateLayout)
            invalidateParentSizeAndDisplayList();

        if (was3D != is3D)
            validateMatrix();
    }

    /**
