     override protected function unloadSkin():void
     {    
         uninstallViewport();
+        skin.layout = null;
         super.unloadSkin();
     }
     

            viewport.clipContent = false;
            skin.removeElement(viewport);
            viewport.removeEventListener(PropertyChangeEvent.PROPERTY_CHANGE, viewport_propertyChangeHandler);
        }
    }
    

        var vp:IViewport = viewport;
        if (!vp || event.isDefaultPrevented())
            return;
            
        // If a TextField has the focus, then check to see if it's already
        // handling mouse wheel events.  For now, we'll make the same 
        // assumption about TextView.
        var focusOwner:InteractiveObject = getFocus();
        if ((focusOwner is TextField) && TextField(focusOwner).mouseWheelEnabled)
            return;    
        if (focusOwner is TextView)
            return;        

        var nSteps:uint = Math.abs(event.delta);
        var unit:ScrollUnit;
