         var scrollPosition:Number = verticalScrollPosition;
 		
         var itemIndex:int = Math.floor(scrollPosition / rowHeight);
-        var yPos:Number = 0;
+        var yPos:Number;
         var yPosMax:Number;
         
         var foundLastVisibleElement:Boolean = false;

            return;    
        }
        
        var y0:Number = scrollR.top;
        var y1:Number = scrollR.bottom - .0001;
        if (y1 <= y0)
        {
            setIndexInView(-1, -1);

        else
        {
            if (!firstElement || !lastElement || 
                (y0 < firstElement.getLayoutBoundsY() && firstIndexInView != 0) || 
                (y1 >= (lastElement.getLayoutBoundsY() + lastElement.getLayoutBoundsHeight()) && lastIndexInView != n))
            {
                g.invalidateDisplayList();
            }
