How to have vertical scroll bar to cover the bottom padding area of a ListGrid

I'm trying to keep some padding on the bottom of a ListGrid.

setPadding(10);
setPaddingAsLayoutMargin(false);

When the vertical scroll bar shows, I don't see any padding on the bottom. Is this a bug? Thanks!

I'm using SmartClient Version: v9.1p_2014-07-08/PowerEdition Deployment (built 2014-07-08) and Firefox 17.0.9.