Re: mouse-drag-and-drop-region

[martin rudalics]

> Obsoleting such a veteran feature needs a very good reason, because it
> causes annoyances across the community, as it's most probably is used
> in a lot of places outside of the Emacs tree.  If the only reason we
> have is that there are some disadvantages in some corner cases, it's
> not enough to obsolete the form, IMO.

Yes.  I already said that I don't fully understand the arguments against
`read-event'.

> Why would it be unsafe wrt redisplay?

Because of that part of tracking_off:

      /* Redisplay may have been preempted because there was input
         available, and it assumes it will be called again after the
         input has been processed.  If the only input available was
         the sort that we have just disabled, then we need to call
         redisplay.  */
      if (!readable_events (READABLE_EVENTS_DO_TIMERS_NOW))
        {
          redisplay_preserve_echo_area (6);
          get_input_pending (READABLE_EVENTS_DO_TIMERS_NOW);
        }

IIUC we don't do that in `mouse-drag-track'.

martin