(gdb) bt
#0  0xb77140ac in g_type_check_instance_cast ()
   from /usr/lib/libgobject-2.0.so.0
#1  0x0808ae6d in do_add_cb (widget=0x823cae0, resp=-3, s=0x874f5c8)
    at gtkconv.c:3989
#2  0xb770415b in g_cclosure_marshal_VOID () from /usr/lib/libgobject-2.0.so.0
#3  0xb76f707b in g_closure_invoke () from /usr/lib/libgobject-2.0.so.0
#4  0xb77074e9 in signal_emit_unlocked_R () from /usr/lib/libgobject-2.0.so.0
#5  0xb77089a9 in g_signal_emit_valist () from /usr/lib/libgobject-2.0.so.0
#6  0xb7708b59 in g_signal_emit () from /usr/lib/libgobject-2.0.so.0
#7  0xb79cfd88 in gtk_dialog_response () from /usr/lib/libgtk-x11-2.0.so.0
#8  0xb79cfde5 in action_widget_activated () from /usr/lib/libgtk-x11-2.0.so.0
#9  0xb770440b in g_cclosure_marshal_VOID__VOID ()
   from /usr/lib/libgobject-2.0.so.0
#10 0xb76f707b in g_closure_invoke () from /usr/lib/libgobject-2.0.so.0
#11 0xb77074e9 in signal_emit_unlocked_R () from /usr/lib/libgobject-2.0.so.0
#12 0xb77089a9 in g_signal_emit_valist () from /usr/lib/libgobject-2.0.so.0
#13 0xb7708b59 in g_signal_emit () from /usr/lib/libgobject-2.0.so.0
#14 0xb7983c91 in gtk_button_clicked () from /usr/lib/libgtk-x11-2.0.so.0
#15 0xb79858ec in gtk_real_button_released () from /usr/lib/libgtk-x11-2.0.so.0
#16 0xb770440b in g_cclosure_marshal_VOID__VOID ()
   from /usr/lib/libgobject-2.0.so.0
#17 0xb76f5639 in g_type_class_meta_marshal ()
   from /usr/lib/libgobject-2.0.so.0
#18 0xb76f707b in g_closure_invoke () from /usr/lib/libgobject-2.0.so.0
#19 0xb7707966 in signal_emit_unlocked_R () from /usr/lib/libgobject-2.0.so.0
#20 0xb77089a9 in g_signal_emit_valist () from /usr/lib/libgobject-2.0.so.0
#21 0xb7708b59 in g_signal_emit () from /usr/lib/libgobject-2.0.so.0
#22 0xb7983d21 in gtk_button_released () from /usr/lib/libgtk-x11-2.0.so.0
#23 0xb7983d81 in gtk_button_button_release ()
   from /usr/lib/libgtk-x11-2.0.so.0
#24 0xb7a526c2 in _gtk_marshal_BOOLEAN__BOXED ()
   from /usr/lib/libgtk-x11-2.0.so.0
#25 0xb76f5639 in g_type_class_meta_marshal ()
   from /usr/lib/libgobject-2.0.so.0
#26 0xb76f707b in g_closure_invoke () from /usr/lib/libgobject-2.0.so.0
#27 0xb7707b1d in signal_emit_unlocked_R () from /usr/lib/libgobject-2.0.so.0
#28 0xb7708788 in g_signal_emit_valist () from /usr/lib/libgobject-2.0.so.0
#29 0xb7708b59 in g_signal_emit () from /usr/lib/libgobject-2.0.so.0
#30 0xb7b632e4 in gtk_widget_event_internal ()
   from /usr/lib/libgtk-x11-2.0.so.0
#31 0xb7a4baf3 in gtk_propagate_event () from /usr/lib/libgtk-x11-2.0.so.0
#32 0xb7a4ccd7 in gtk_main_do_event () from /usr/lib/libgtk-x11-2.0.so.0
#33 0xb78e1a1a in gdk_event_dispatch () from /usr/lib/libgdk-x11-2.0.so.0
#34 0xb74e3951 in g_main_context_dispatch () from /usr/lib/libglib-2.0.so.0
#35 0xb74e69af in g_main_context_iterate () from /usr/lib/libglib-2.0.so.0
#36 0xb74e6d67 in g_main_loop_run () from /usr/lib/libglib-2.0.so.0
#37 0xb7a4d151 in gtk_main () from /usr/lib/libgtk-x11-2.0.so.0
#38 0x080aedc1 in main (argc=1836017711, argv=0x61732f65) at gtkmain.c:817