bug#59733: 29.0.50; unresponsive Xaw menus

[Po Lu via "Bug reports for GNU Emacs, the Swiss army knife of text editors" <bug-gnu-emacs@gnu.org>]

Madhu <enometh@meer.net> writes:

> Thanks, unfortunately this looks like a genuine heisenbug and my
> earlier reports should be deemed unreliable.  I do have builds which
> "don't work" but I'm am now unable to produce *new* builds which
> "don't work", (say with adding printf debugging or resetting)
>
> AFAICT both XtGrabPointer and XtGrabKeyboard return Success in all
> cases (both "works" and "doesn't work" builds) - keyboard and pointer
> are both grabbed as expected - from gdb dprintfs, disassembly seems
> identical.
>
> The only significant thing I can report (I have libinput
> enable-tab=true) on a "doesn't work" build is that if i quickly make
> two single taps on the help button on the toolbar, on the touchpad,
> then the pop-up-menu "works".  (the effect seems to be an event
> between the activation of the menu and the display of the menu - F10
> doesn't work as usual). There hasn't been any progress Sorry

This might be a stab in the dark, but:

Can you run both builds that "work" and those that "don't work" under
Valgrind and see if there is some memory problem causing this?

Make sure to run Emacs with "--eval (setq gc-cons-threshold
most-positive-fixnum)" specified on the command line, or false positives
will be reported during GC.