Work around GNOME Shell app submenu bug
    
    See https://gitlab.gnome.org/GNOME/gnome-shell/-/issues/2878 .
    GNOME 3.37.2 seems to have a bug with submenus in the app menu;
    the first time you open one you can't scroll through it using
    the keyboard. On every open after the first it works fine. This
    is a quick and dirty workaround - when we're dealing with a
    submenu, open it then close it then open it again.
    
    Signed-off-by: Adam Williamson <awilliam@redhat.com>