> From: Glenn Morris <rgm@gnu.org>
> Cc: dmantipov@yandex.ru,  17497@debbugs.gnu.org
> Date: Fri, 16 May 2014 11:47:27 -0400
> 
> > Does this problem go away if you enlarge the terminal window such that
> > the entire File and Tools menus can be displayed without overlaying
> > the mode line? 
> 
> I maximized the xterm before starting Emacs, and still very quickly got
> into the state where there is a duplicate "--" off to the right of the
> real menu (same as my "1.png" from earlier). It does seem less common
> with a bigger terminal though.
> 
> > Does this happen if you use the menu "reasonably", i.e. without
> > leaning on arrow keys? 
> 
> So far no, IME.
> 
> > Does it happen if you use C-p instead of the down arrow?
> 
> Leaning on C-p produces glitches, yes. Here's a fun one:

Could both of you please record the terminal commands issued while you
reproduce the problem in a termscript, and then replay that termscript
to the same terminal (outside Emacs) with the attached shell script?
I'm interested to see whether the problem is reproduced by sending the
same commands at a low rate.

If sleeping for 2 seconds doesn't reproduce the problem, maybe try
decreasing the sleep time until it does.

TIA