I have this problem as well. Disabling the Gnome extension Ubuntu AppIndicators and rebooting works as a workaround.
-- You received this bug notification because you are a member of Ubuntu Desktop Bugs, which is subscribed to gnome-shell-extension-appindicator in Ubuntu. https://bugs.launchpad.net/bugs/2012388 Title: X11 window at top-right of the screen is invisible and steals mouse clicks To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/gnome-shell-extension-appindicator/+bug/2012388/+subscriptions -- desktop-bugs mailing list desktop-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/desktop-bugs