I think this is upstream bug https://gitlab.gnome.org/GNOME/mutter/issues/655.
The bug has been solved by: https://gitlab.gnome.org/GNOME/mutter/merge_requests/924 https://gitlab.gnome.org/GNOME/gnome-shell/merge_requests/815 It is a quite critical bug since it renders the shell unusable. Would you consider backporting these patches to 18.04? ** Bug watch added: gitlab.gnome.org/GNOME/mutter/issues #655 https://gitlab.gnome.org/GNOME/mutter/issues/655 -- You received this bug notification because you are a member of Desktop Packages, which is subscribed to gnome-shell in Ubuntu. https://bugs.launchpad.net/bugs/1844222 Title: Wayland session overlaid by window when fullscreen SDL apps exits Status in gnome-shell package in Ubuntu: Confirmed Status in mutter package in Ubuntu: Confirmed Bug description: Seen on 18.04 and 19.10 In the "Ubuntu Wayland" desktop sudo apt install beneath-a-steel-sky SDL_VIDEODRIVER=wayland scummvm -f -p /usr/share/scummvm/beneath-a-steel-sky sky Press ESC a few times and Ctrl-Q to exit. Expect: session returns to normal Actual: a black rectangle covers the screen, even when switching workspaces. (I'm sure scummvm is doing something odd, but...) To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/gnome-shell/+bug/1844222/+subscriptions -- Mailing list: https://launchpad.net/~desktop-packages Post to : desktop-packages@lists.launchpad.net Unsubscribe : https://launchpad.net/~desktop-packages More help : https://help.launchpad.net/ListHelp