When playing full screen FPS games, such as Ballistic Overkill, or Xonotic, you fairly readily produce an issue where your weapon does not stop firing on mouse up.

Steps to reproduce:
Open a FPS, start shooting continously, and turn left at the same time, with a top left screen edge enabled (in my case present windows).

If the screen edge is disabled, this issue will not happen.

What seems to be occuring, is that while turning left, your mouse triggers the screen edge without any visual indicator, which then causes your game to stop behaving as expected.