We are experiancing the same thing, except ours is happening at the top not the bottom. We are finding Revit 2010 very hard to work with. The tools in the ribbon jump around (I am always looking for my tools), the screen jumps as just said, and it crashes every 10 minutes, then it takes 5 minutes to open rework our lost 10 minutes from the crash and then work another few minutes till it crashes again. We try to save frequently but even the save to central takes 2, 3, 4 minutes as well. We are finding Revit 2010 to be very unproductive.