Shotcut version 22.01.30
Ubuntu Linux 20.04 (Kernel 5.4.0-99-generic)
Timeline window just goes blank. Menus, content (video and audio) all just disappear. Different actions can cause this and the only way to recover is to save the project, quit Shotcut and then restart it. Opening the project restores the timeline view for a while however, after a few edits and/or additions, it just disappears again and you need to save/quit/restart/reload all over again.