      */
     override protected function mouseClickHandler(event:MouseEvent):void
     {
-        if (!tween)
+        if (!tween && visibleColumns && visibleColumns.length > 0)
             super.mouseClickHandler(event);
     }
 

     */
    override protected function mouseDownHandler(event:MouseEvent):void
    {
        if (!tween)
        {
            super.mouseDownHandler(event);
            updateSelectedCells();

     */
    override protected function mouseUpHandler(event:MouseEvent):void
    {
        if (!tween && visibleColumns && visibleColumns.length > 0)
            super.mouseUpHandler(event);
    }

