Hi, unfortunately KWin 6.3.0 has a somewhat severe crash issue on X11. See https://bugs.kde.org/show_bug.cgi?id=499846 The fix is https://invent.kde.org/plasma/kwin/-/commit/c97bc26ca9de8b1462f6ccb05fb2dafe01cd82cb and will be part of 6.3.1, but you might want to apply it earlier. Cheers Nico