bug#53916: 29.0.50; pgtk: Gtk-WARNING with popup menu

[Eli Zaretskii]

> Resent-From: Po Lu <luangruo@yahoo.com>
> Original-Sender: "Debbugs-submit" <debbugs-submit-bounces@debbugs.gnu.org>
> Resent-CC: bug-gnu-emacs@gnu.org
> Resent-Sender: help-debbugs@gnu.org
> Cc: Stephen Berman <stephen.berman@gmx.net>, 53916@debbugs.gnu.org
> Date: Thu, 10 Feb 2022 21:31:17 +0800
> From:  Po Lu via "Bug reports for GNU Emacs,
>  the Swiss army knife of text editors" <bug-gnu-emacs@gnu.org>
> 
> Robert Pluim <rpluim@gmail.com> writes:
> 
> >     Po> That warning is harmless, though we could make it go away by 
> > installing
> >     Po> a log handler.  Someone else should chime in at this point to decide
> >     Po> whether or not that's worth it, since such a filter might end up
> >     Po> obscuring legitimate problems in the future.
> >
> > Can such a log handler put those warnings in *Messages*?
> 
> Yes.

I wouldn't recommend mixing GTK diagnostics with *Messages*.  Why not
have a separate buffer for the GTK messages?