The question mark is in there because I don't know if this is a bug or not.
Let's say, like now, I'm running a 1280x1024 desktop.
If I set the game to be windowed mode and the resolution to 1280x1024, the game will end up being fullscreen anyway. However, if I set it to 1024x768, then it will be in a window.
Not sure if this is a bug or no, but I figure I'd report it and await dev. response.
Debug.err attached