[propbeanie]

That is usually caused by the player "shelling-out" to Windows with the game still running. SH4 gets confused when that happens, and the games "loses focus", and is not able to take care of itself properly. The easiest way to get rid of that is to Save the game, exit the game, re-start it, then load the Save, and you should be good to go. On some computers, you can pause the game, then use the Windows key to go do something, and not have issue when returning. Other computers, it is a no-go situation no matter what you do. It is best to avoid if at all possible. If you are running a mod, your chances of encountering this are generally higher.