Comment 4 for bug 829367

StacktraceTop:
 g_type_check_instance_cast (type_instance=0xb6b20620, iface_type=135088432) at /build/buildd/glib2.0-2.29.16/./gobject/gtype.c:3985
 notify_cb (obj=0x81832a8, pspec=0x80cc600) at /build/buildd/gtk+3.0-3.1.12/./gtk/a11y/gtkwidgetaccessible.c:62
 g_cclosure_marshal_VOID__PARAM (closure=0x8213150, return_value=0x0, n_param_values=2, param_values=0x821af90, invocation_hint=0xbf92e7b0, marshal_data=0x0) at /build/buildd/glib2.0-2.29.16/./gobject/gmarshal.c:539
 g_closure_invoke (closure=0x8213150, return_value=0x0, n_param_values=2, param_values=0x821af90, invocation_hint=0xbf92e7b0) at /build/buildd/glib2.0-2.29.16/./gobject/gclosure.c:773
 signal_emit_unlocked_R (node=0x80c23d8, detail=96, instance=0x81832a8, emission_return=0x0, instance_and_params=0x821af90) at /build/buildd/glib2.0-2.29.16/./gobject/gsignal.c:3271