Huh? You're the first to describe that behavior... How is it exiting out of diablo? Do you have an older system/old laptop?
Also, little update: Everything is currently working in 800x600 windowed mode. You can move the window anywhere without any problems I just need to make the code neat and quickly combine the two code bases (1080P and 800x600 are currently in 2 separate source files but I'm writing a system to make it all one big neat piece of code). Still have a few kinks to fix but it's mostly done.