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

            }
           
            // If gridDimensions.rowHeight is now larger, we need to make another
            // pass to fix up the item renderer heights.           
            const finalRowHeight:Number = gridDimensions.getRowHeight(rowIndex);
            if (rowHeight != finalRowHeight)
            {

        
        // Only invalidate if we're clipping and scrollR extends outside validBounds
        
        const scrollR:Rectangle = grid.scrollRect;
        if (scrollR && !visibleItemRenderersBounds.containsRect(scrollR))
            grid.invalidateDisplayList();
