Just an information question... I was modeling in an assembly, realized I didn't like the design, so I was using the "Undo" button to go back about 6 steps or so.  I was clicking fairly fast, and when I hit the second click everything I'd done that session was undone.  Didn't cause a problem (actually kinda nice... the model danced around the screen in the reverse of the view rotations, the parts danced to the inserted positions... very Disney), but I'm wondering if Windows recognized it as a double-click.  If you double-click the Undo, does it undo back to the beginning of the session??