bug#57320: 29.0.50; Lucid menus can't be operated with the mouse

[Visuwesh]

[திங்கள் ஆகஸ்ட் 22, 2022] Po Lu wrote:

> Please put a breakpoint on line 2879 of xlwmenu.c and tell me what
> XtGrabPointer returns.  Make sure to do this from another machine, since
> grabbing will not work if you switch windows or click anywhere else.

I wasn't sure how to make gdb tell me what XtGrabPointer returned but I
said `s' after the breakpoint hit and it jumped to line 2890 so I think
it means XtGrabPointer returned Success?  Anyway, here's the *gud-emacs*
buffer,

    (gdb) run -Q
    Starting program: /home/viz/lib/ports/emacs/src/emacs -Q
    [Thread debugging using libthread_db enabled]
    Using host libthread_db library "/lib/x86_64-linux-gnu/libthread_db.so.1".
    [New Thread 0x7ffff15fe640 (LWP 56454)]
    [New Thread 0x7ffff0c6d640 (LWP 56455)]
    [New Thread 0x7fffebfff640 (LWP 56456)]

    Thread 1 "emacs" hit Breakpoint 3, pop_up_menu (mw=0x55555617dfe0, 
event=0x7fffffffd5a0) at xlwmenu.c:2879
    2879          if (XtGrabPointer ((Widget)mw, False,
    (gdb) s
    2890                  && lucid__menu_grab_keyboard


[ P.S. What is the right value way to do get what XtGrabPointer
  returned?  This is most probably suboptimal.  ]