Add alternative full screen shortcut Ctrl+Cmd+F
On Mac OS X, the standard Enter/Exit Full Screen shortcut is [Ctrl]+[Cmd]+[F]. MuseScore uses [Cmd]+[U]. There's no need to remove the existing shortcut, but defining the additional standard shortcut would be helpful.
If I understand correctly, the shortcut would need to be defined as [Meta]+[Ctrl]+[F] in order for Qt to convert it to [Ctrl]+[Cmd]+[F] on OS X.