(slab:24511): GLib-GObject-CRITICAL **: g_object_set_data: assertion `G_IS_OBJECT (object)' failed

(slab:24511): GLib-GObject-WARNING **: invalid (NULL) pointer instance

(slab:24511): GLib-GObject-CRITICAL **: g_signal_connect_data: assertion `G_TYPE_CHECK_INSTANCE (instance)' failed