If opened from a past full screen adventure - it will open in full screen and there is no obvious way to exit full screen. It isn't Exc - or cnt-f or cnt-f (Going to a second computer and searching the web - turns out F11 is the trick) Looks like it is being fixed finnaly but - wanted to post this bug as a breadcrumb for others. https://gitlab.gnome.org/GNOME/meld/-/issues/735 https://gitlab.gnome.org/GNOME/meld/-/issues/716