      *  @playerversion AIR 1.5
      *  @productversion Flex 4
      */
-    public function getVerticalScrollPositionDelta(scrollUnit:uint):Number
-    {
-        return (layout) ? layout.getVerticalScrollPositionDelta(scrollUnit) : 0;     
+    public function getVerticalScrollPositionDelta(navigationUnit:uint):Number
+    {
+        return (layout) ? layout.getVerticalScrollPositionDelta(navigationUnit) : 0;     
     }
     
     //--------------------------------------------------------------------------

     *  @private
     *  Storage for the mouseOpaque property
     */
    private var _mouseOpaque:Boolean = true;
    protected var mouseEventReferenceCount:int;

    [Inspectable(category="General")]
    

    }
    
    /**
     *  @private
     *  Called when the child transform changes (currently x and y on UIComponent),
     *  so that the Group has a chance to invalidate the layout. 
     */
    override mx_internal function childXYChanged():void
    {
        if (autoLayout)
        {
