bug#46990: 28.0.50; popup menu not navigable via arrow keys on lucid build

[Eli Zaretskii]

> From: Colin Baxter <m43cap@yandex.com>
> Date: Wed, 10 Mar 2021 18:59:19 +0000
> Cc: "Basil L. Contovounesios" <contovob@tcd.ie>, , 46990@debbugs.gnu.org
> 
> >>>>> Glenn Morris <rgm@gnu.org> writes:
> 
>     > FWIW I can reproduce this in the emacs-27 (and master) branch on
>     > 64-bit RHEL and Debian, but so far it disappears when bisecting.
>     > I don't see it in installed 26.{1,2,3} or 27.1, but I do in an old
>     > uninstalled emacs-26 branch build.  Weird.
> 
> I have compiled my emacs-27.1 with lucid and the effect does not
> occur. I can navigate menus with arrow keys and mouse.

Thanks.  Does that mean the problem started between 27.1 and 27.1.91?
If so, can you please bisect between these two points?