From time to time, my mouse decides that it doesn't want to provide any input to the application. This ranges from doing nothing when I mouse-over the hot corner, to not delivering scroll events from the wheel, to not clicking when the buttons are pressed. I can resolve this issue, it would seem, by closing some windows, maybe killing the X-Server in the process. Some googling suggests that this may be an issue where an application has "grabbed" the mouse and not released it. There's nothing (obvious) in my logs.
Any ideas what might be the culprit?