Daniel,
You can put code in the MouseUp to conditionally issue a NODEFAULT. That will prevent the scroll from ever happening in the first place.
>i have a split grid. on the right side i've traped the scrolled event to prevent the grid from scrolling back past a col. The problem is that just for a second you can see the unwanted colunm before the doscroll pushes the unwanted col off the left side. I've tried using lockscreen in the scrolled event but the scroll has already happend by the time the code gets to there. I need to prevent the tearing.