      */
     private const visibleItemRenderersBounds:Rectangle = new Rectangle();
     
+    /**
+     *  Initialized by updateDisplayList with the current scrollPosition, and grid.width,Height.
+     */
+    private const visibleGridBounds:Rectangle = new Rectangle();
+    
+    
     private function layoutItemRenderers(itemRendererGroup:Group, scrollX:Number, scrollY:Number, width:Number, height:Number):void
     {
         var rowIndex:int;

        
        const scrollX:Number = horizontalScrollPosition;
        const scrollY:Number = verticalScrollPosition;
        
		updateGridDimensions(scrollX, scrollY, unscaledWidth, unscaledHeight);


    {
        const r:Rectangle = visibleItemRenderersBounds;
        const width:Number = 1;  // TBD: should be max(1, rowGap)
        const height:Number = Math.max(r.height, visibleGridBounds.height); 
        const bounds:Rectangle = gridDimensions.getColumnBounds(columnIndex);
        if (!bounds)
            return;
