SDL2 sets this on windows by default, which is likely what's doing it: https://specifications.freedesktop.org/wm-spec/wm-spec-latest.html#idm46035372472224 htt

SDL2 sets this on windows by default, which is likely what's doing it: https://specifications.freedesktop.org/wm-spec/wm-spec-latest.html#idm46035372472224 https://specifications.freedesktop.org/wm-spec/wm-spec-lates... Compositing is required for any sort of antialiasing, especially including window borders, so it's difficult to turn off without having a lot of artifacts. And it also solves vsync which a lot of raw X11 applications can't possibly render correctly with.