Reproducible crash on "menu open + ESC"

Click open a menu, then press ESC key (on keyboard, i mean). A dialog appears 
saying "Internal error: Segmentation fault (core dumped)".
If i click "ignore", a new menu appears and i can continue, so the issue is 
not severe (I guess).

Since the problem appears sistematically on graphic widgets manipulation, I 
didn't run "ddd --trace" because i find it highly unlikely to be a problem 
with the inferior debugger.

I kept the dumped core file, available on request.

$ ddd --configuration
ddd: Symbol `_XmStrings' has different size in shared object, consider 
re-linking
GNU DDD 3.3.11 (i486-pc-linux-gnu)
Copyright (C) 1995-1999 Technische Universit�t Braunschweig, Germany.
Copyright (C) 1999-2001 Universit�t Passau, Germany.
Copyright (C) 2001 Universit�t des Saarlandes, Germany.
Copyright (C) 2001-2004 Free Software Foundation, Inc.

Compiled with GCC 4.0.2 20050808 (prerelease) (Ubuntu 4.0.1-4ubuntu9), GNU 
libc 2.3
Requires X11R6, Xt11R6, Motif 2.1 (GNU/LessTif Version 2.1 Release 0.93.94)
Includes XPM 3.4.11, Athena Panner (7000002L), DDD core
Built 2005-10-25 by Daniel Schepler <[email protected]>.
-- 
Best regards,
Juan