[Karmic Alpha 5] ubuntu-bug repeted crashes - Gdk-ERROR - 'BadWindow (invalid Window parameter)' when communicating with Firefox

Binary package hint: apport

When reporting bugs against indicator-applet and apport itself using ubuntu-bug, I faced successive identical crashes for about 10 times before 2 reports passed through.

The crash was not picked up by apport like it usually is.

The terminal error message was:
Gdk-ERROR **: The program 'firefox' received an X Window System error.
This probably reflects a bug in the program.
The error was 'BadWindow (invalid Window parameter)'.
  (Details: serial 1287 error_code 3 request_code 20 minor_code 0)
  (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.)
aborting...

(I didn't manage to run ubuntu-bug with the --sync option)

ProblemType: Bug
Architecture: i386
CrashReports:
 600:1000:1000:12833943:2009-09-07 00:33:00.537470000 +0200:2009-09-07 00:33:04.529470725 +0200:/var/crash/_usr_bin_totem.1000.crash
 600:1000:1000:32216:2009-09-07 01:37:33.792529000 +0200:2009-09-07 01:37:37.701028716 +0200:/var/crash/_usr_share_apport_apport-gtk.1000.crash
 600:1000:1000:832048:2009-09-06 22:51:41.337460000 +0200:2009-09-06 22:51:42.337460000 +0200:/var/crash/_usr_lib_firefox-3.5.2_firefox.1000.crash
 600:1000:1000:520109:2009-09-07 00:22:40.269460000 +0200:2009-09-07 00:22:44.961459821 +0200:/var/crash/_usr_bin_pulseaudio.1000.crash
Date: Mon Sep 7 10:01:36 2009
DistroRelease: Ubuntu 9.10
NonfreeKernelModules: nvidia
Package: apport 1.8.2-0ubuntu1
PackageArchitecture: all
ProcEnviron:
 LANG=fr_FR.UTF-8
 SHELL=/bin/bash
ProcVersionSignature: Ubuntu 2.6.31-9.29-generic
SourcePackage: apport
Uname: Linux 2.6.31-9-generic i686