These are used for display switching, and even though you could
remap these shortcuts, it would work only until you close an image,
open a new one, or reorder tabs in SWM, in which case your shortcut
would end up forcefully overrided, which is a bad user experience.
If we want to give more flexibility and allow one to map these
shortcuts, we must also make sure the display showing actions won't
override customized shortcuts. In the meantime, it is better to
simply forbid these in our preferences.