First, any mode change causes the display to "grab" the underlying/previous graphics and hold them in the window for a moment before updating. Some screenshots in spoiler below, click for fullsize.[spoiler]Scaling DOWN a windowed mode

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Scaling UP a windowed mode
[/spoiler]Now, that's annoying but not too big a deal, but the next problem is worse. Running in fullscreen in less than native resolution does not scale to fit the display. Screenshot in spoiler. [spoiler]
[/spoiler]I've tested both ZDoom, Chocolate Doom, and Amnesia: The Dark Descent in non-native resolutions and all work 100% properly (supplementary screenshot). Additionally, switching to/from fullscreen also displays the same behavior noted above.[spoiler]Switching out of fullscreen
[/spoiler]Honestly this isn't the end of the world, but it's certainly annoying and makes me enjoy GZDoom on Linux slightly less. Hope it's maybe possible to fix somehow.
