Prevent second monitor to "move" while in fullscreen games
This is because of the resolution of the game. If the game resolution doesn't match the normal resolution you use outside of the game, the resolution will change and cause strange effects on the other monitors. This works from left to right, so if you play the game on your right-most monitor, you will never experience this.
The solution is to play the game in the same resolution that you use normally for your monitor, or to run the game in a window so that the monitor resolution need not be changed.