[O] org-read-date and (setq pop-up-frames 'graphic-only)

[Tom Prince]

 With (set pop-up-frames 't), org-read-date behaves badly, creating
calendar in the bottom. (setq calendar-setup 'calendar-only) would fix
this, but org-read-date overrides it. A new frame for the calendar. But
the frame is split, with the calendar at the bottom, and some random
buffer at the top.

Is there any reason that org-read-date is overriding calendar-setup, or
could this be made customizable?

  Tom