Steps to reproduce: 1. Start gtk4-demo 2. Try to move the main window If you start moving the window in any dirrection except up, the window wouldn't move. Gtk4-git Archlinux Plasma 5.13.2 Xorg video: https://gfycat.com/gifs/detail/CrispEnchantedBarb I know this sounds like a gtk issue but I have been told that it is probably a Kwin issue. https://gitlab.gnome.org/GNOME/gtk/issues/1195
Clearly a toolkit bug.