      *  Taking into account which modifier keys were clicked, the new
      *  selectedIndices interval is calculated. 
      */
-    private function calculateSelectedIndicesInterval(renderer:IVisualElement, shiftKey:Boolean, ctrlKey:Boolean):Vector.<Number>
+    private function calculateSelectedIndicesInterval(renderer:IVisualElement, shiftKey:Boolean, ctrlKey:Boolean):Vector.<int>
     {
         var i:int; 
-        var interval:Vector.<Number> = new Vector.<Number>();  
+        var interval:Vector.<int> = new Vector.<int>();  
         var index:Number = dataGroup.getElementIndex(renderer); 
         
         if (!shiftKey)

     *  selection, this is just selectedIndex. In multiple 
     *  selection, this is the index of the first selected item.  
     */
    private function getFirstSelectedIndex():Number
    {
        if (selectedIndices && selectedIndices.length > 0)
            return selectedIndices[0]; 

     */
    protected function commitMultipleSelection():void
    {
        var removedItems:Vector.<int> = new Vector.<int>();
        var addedItems:Vector.<int> = new Vector.<int>();
        var i:int;
        var count:int;
        
