Comment 1 for bug 220628

Update. No core file is produced, and running firefox under gdb gives nothing. The "apt-cache search firefox debug" command does not show any package related to firefox-3.
The problem reproduces fairly regularly. Example of a gdb session:

$ ulimit -c
10000
$ gdb
[...]
(gdb) file /usr/lib/firefox-3.0b5/firefox
Reading symbols from /usr/lib/firefox-3.0b5/firefox...(no debugging symbols found)...done.
(gdb) break gdk_x_error
Function "gdk_x_error" not defined.
Make breakpoint pending on future shared library load? (y or [n]) y
Breakpoint 1 (gdk_x_error) pending.
(gdb) run --sync
[...]
[New Thread 0x40c5d950 (LWP 24772)]
[Thread 0x40c5d950 (LWP 24772) exited]
[New Thread 0x40c5d950 (LWP 24773)]
The program 'firefox' received an X Window System error.
This probably reflects a bug in the program.
The error was 'BadIDChoice (invalid resource ID chosen for this connection)'.
  (Details: serial 147095966 error_code 14 request_code 153 minor_code 4)
  (Note to programmers: normally, X errors are reported asynchronously;
   that is, you will receive the error a while after causing it.
   To debug your program, run it with the --sync command line
   option to change this behavior. You can then get a meaningful
   backtrace from your debugger if you break on the gdk_x_error() function.)

Program exited with code 01.
(gdb) quit

I'm still confused as to what I could or should do to help pin down the source of the trouble.