Scroll Bars

How can I have the grid scroll while the user has "grabbed" the scroll bar and is pulling down the scroller. Currently, the grid does not re-position until the user has released the scroll bar. I thought a property of VScrollBehavior would produce this behavior, but the grid itself doesn''t seem to scroll until the user has released the scroll bar. Thanks, Steve

Try setting grid.VerticalThumbTrack = true;