it happen in TD series for a long time, from TD1 to TD2, for an example, when i set the game resolution at 2k, my native monitor was 4k or other resolution that is different from game setting itself, it will not display in full screen mode, even u set it . i hope there was a fix for this. as i think full screen to play this game is better than in window mode or above glitch mode, as it will not display in full screen mode, even i set it in game setting or GPU scaling on GPU software itself.