         multipleSelectionChanged = true;
         invalidateProperties(); 
     }
+
+    //----------------------------------
+    //  useVirtualLayout
+    //----------------------------------
 
     /**
      *  @inheritDoc

        useVirtualLayout = true;
    }
    
    //----------------------------------
    //  scroller
    //----------------------------------


package spark.components
{ 
import flash.display.DisplayObject;
import flash.events.KeyboardEvent;
import flash.events.MouseEvent;
import flash.events.FocusEvent;
