     /**
      *  @private
      *  Called when the viewport's <code>verticalScrollPosition</code> value changes. Does nothing by default. 
-     *  
-     *  @langversion 3.0
-     *  @playerversion Flash 10
-     *  @playerversion AIR 1.5
-     *  @productversion Flex 4
      */
     mx_internal function viewportVerticalScrollPositionChangeHandler(event:PropertyChangeEvent):void
     {

    /**
     *  @private
     *  Called when the viewport's <code>horizontalScrollPosition</code> value changes. Does nothing by default.
     *  
     *  @langversion 3.0
     *  @playerversion Flash 10
     *  @playerversion AIR 1.5
     *  @productversion Flex 4
     */
    mx_internal function viewportHorizontalScrollPositionChangeHandler(event:PropertyChangeEvent):void
    {

   /**
    *  @private
    *  Called when the viewport's <code>contentWidth</code> value changes. Does nothing by default.
    */
    mx_internal function viewportContentWidthChangeHandler(event:PropertyChangeEvent):void
    {
