I've had this problem and thought it was probably just on my end so I've just sort of been dealing with it. It seems that randomly, when moving the mouse around, my window simply closes. This has happened across multiple projects and now with multiple computers, and I'm not sure where the issue lies.
I recently started coding with a friend (using Git) and he also has the same problem. We're both using VS12 and got the precompiled packages from exploit's nightly builds. If you don't move the mouse, there is no problem. When you do move the mouse, within a few seconds (usually) the window closes on it's own.
I can't seem to find any answers on Google about this particular issue.