bug#38038: 27.0.50; Emacs freezes opening tabs.

[Eli Zaretskii]

> Cc: spacibba@aol.com, juri@linkov.net, 38038@debbugs.gnu.org
> From: martin rudalics <rudalics@gmx.at>
> Date: Sat, 9 Nov 2019 10:02:36 +0100
> 
> The below makes the bug go away for the tool bar, I didn't try for the
> tab bar.

Thanks.

> I can continue working on this after we decided whether to ask for
> pseudo-windowness or just use the BUFFERP predicate as I did.

It doesn't really matter, AFAIK, but BUFFERP is clearer, I think.