bug#7092: 23.1; Dired slow using Emacs remotely

[Eli Zaretskii]

> From: Stefan Kangas <stefan@marxist.se>
> Date: Fri, 22 Oct 2021 01:12:28 -0700
> Cc: despen@telcordia.com, 7092@debbugs.gnu.org
> 
> Eli Zaretskii <eliz@gnu.org> writes:
> 
> >> IOW, should we just document somehow that if you are using X forwarding,
> >> you might want to disable mouse highlighting?
> >
> > Maybe this is all that's needed, yes.
> 
> Hmm, I wonder where this should best go.  etc/PROBLEMS perhaps?

I had the doc string in mind, but we could also add something to
PROBLEMS.