Ive changed this BorderlessWindow line and there the same problem. Didnt react on Alt+Tab, when I use Alt+Enter, black screen shows for half second, and back into game. I've got GOG version, maybe thats a problem? And if I remember, i didint install fullscreen fix ( or something like that ) , because it wasnt necessary to play on fullscreen on this platform. What you think? Should I buy Steam version?