Comment 4 for bug 426828

happen again with Firefox 3.5.5
Ubuntu lucid (development branch)

[Thread 0x7fffc9e67910 (LWP 4661) exited]
[Thread 0x7fffe6be4910 (LWP 4591) exited]

(firefox:4588): GLib-GObject-WARNING **: instance with invalid (NULL) class pointer

(firefox:4588): GLib-GObject-CRITICAL **: g_signal_handlers_disconnect_matched: assertion `G_TYPE_CHECK_INSTANCE (instance)' failed

Program received signal SIGSEGV, Segmentation fault.
IA__g_type_check_instance (type_instance=0x7fffbfc46d00)
    at /build/buildd/glib2.0-2.22.2/gobject/gtype.c:3802
3802 /build/buildd/glib2.0-2.22.2/gobject/gtype.c: No such file or directory.
 in /build/buildd/glib2.0-2.22.2/gobject/gtype.c
(gdb) bt
#0 IA__g_type_check_instance (type_instance=0x7fffbfc46d00)
    at /build/buildd/glib2.0-2.22.2/gobject/gtype.c:3802
#1 0x00007ffff251499b in IA__g_signal_handlers_disconnect_matched (
    instance=0x7fffbfc46d00, mask=24, signal_id=0, detail=0, closure=0x0,
    func=<value optimized out>, data=0x7fffdc1f8400)
    at /build/buildd/glib2.0-2.22.2/gobject/gsignal.c:2667
#2 0x00007fffda0fbe93 in ?? ()
   from /usr/lib/gtk-2.0/2.10.0/immodules/im-xim.so
#3 0x00007fffda0fbf2b in ?? ()
   from /usr/lib/gtk-2.0/2.10.0/immodules/im-xim.so
#4 0x00007ffff24fd5ae in IA__g_closure_invoke (closure=0x7fffd587c430,
    return_value=0x0, n_param_values=2, param_values=0x7fffbd123040,
    invocation_hint=0x7fffffff96a0)
    at /build/buildd/glib2.0-2.22.2/gobject/gclosure.c:767
#5 0x00007ffff2512983 in signal_emit_unlocked_R (node=0x7ffff679f740,
    detail=<value optimized out>, instance=<value optimized out>,
    emission_return=<value optimized out>,
    instance_and_params=<value optimized out>)
    at /build/buildd/glib2.0-2.22.2/gobject/gsignal.c:3247
#6 0x00007ffff2513d39 in IA__g_signal_emit_valist (instance=0x7ffff67b4190,
    signal_id=<value optimized out>, detail=0, var_args=0x7fffffff9890)
    at /build/buildd/glib2.0-2.22.2/gobject/gsignal.c:2980
#7 0x00007ffff2514283 in IA__g_signal_emit (instance=0x7fffbfc46d00,
---Type <return> to continue, or q <return> to quit---
    signal_id=24, detail=0)
    at /build/buildd/glib2.0-2.22.2/gobject/gsignal.c:3037
#8 0x00007ffff10fd4a2 in gdk_display_close ()
   from /usr/lib/libgdk-x11-2.0.so.0
#9 0x00007ffff4d10298 in MOZ_gdk_display_close (display=0x7ffff67b4190)
    at nsAppRunner.cpp:2480
#10 0x00007ffff4d14405 in XRE_main (argc=<value optimized out>,
    argv=<value optimized out>, aAppData=<value optimized out>)
    at nsAppRunner.cpp:3459
#11 0x000000000040271f in ?? ()
#12 0x00007ffff6be2abd in __libc_start_main (main=<value optimized out>,
    argc=<value optimized out>, ubp_av=<value optimized out>,
    init=<value optimized out>, fini=<value optimized out>,
    rtld_fini=<value optimized out>, stack_end=0x7fffffffe368)
    at libc-start.c:220
#13 0x0000000000401f99 in ?? ()
#14 0x00007fffffffe368 in ?? ()
#15 0x000000000000001c in ?? ()
#16 0x0000000000000001 in ?? ()
#17 0x00007fffffffe6aa in ?? ()
#18 0x0000000000000000 in ?? ()
(gdb)