bug#53298: 29.0.50; GTK3 frame stops updating

[Eli Zaretskii]

> From: martin rudalics <rudalics@gmx.at>
> Date: Tue, 18 Jan 2022 08:29:08 +0100
> Cc: 53298@debbugs.gnu.org
> 
> Eli, is this OK to install on the release branch?  It doesn't affect
> default behavior but leaves us a fire escape for this and similar cases.

Yes, but please remove the reference to bug numbers from the PROBLEMS
entry.  We don't point to bugs there because PROBLEMS is for users who
need a quick and efficient solution TL;DR style.  The reference to the
bugs in the comments to the code is enough.

Thanks.