I noticed this problem while testing r100. It happens because the editor actually crashes when closing down sometimes, and for some reason it "survives" the crash and keeps the window up. I found some possible causes and fixed them in r100, so it ought to be better in r100/r101. I used to get this fairly often in r99 and I haven't had it at all since r100, so I thought it was fixed, but by the sound of these reports I guess not. There must be something else happening. But like others say, it is very difficult to do anything about this if I can't see the problem myself. Is there anything anyone can do to make the bug happen every time?