bug#30800: 26.0.91; unknown crash on macos

[Eli Zaretskii]

> From: Aaron Jensen <aaronjensen@gmail.com>
> Date: Wed, 21 Mar 2018 22:40:33 -0700
> Cc: Eli Zaretskii <eliz@gnu.org>, 30800@debbugs.gnu.org
> 
> > (Original bug report was 18757 and the commit was
> > d9d383147219f8e6a90d4c177e1b454e19acfac9.)
> 
> I do not understand why setting the represented filename where it was
> set originally causes a flicker.

I don't understand, either, especially since I don't see this on w32.

The recipes in bug#18757 seem to indicate that redisplaying the
frame's title, due to the change in the selected buffer, causes the
flickering.  That flickering started happening with the upgrade to
version 10.10 of the OS, so perhaps it's no linger an issue with the
current OS versions?

> It's probably a dumb question, but would using the start/stop paint
> stuff from the flicker bug help to eliminate the flicker in some way?

Do you still see the flicker if you revert the above commit?