Doing this:

g_object_set (o, "a", ..., "b", ..., NULL)

or this:

g_object_freeze_notify(o);
g_object_notify(o, "a");
g_object_notify(o, "b");
g_object_thaw_notify(o);

causes the notify signal to be emitted twice, in the inverse order in which the properties were set/notified:

notify::b
notify::a

Since this is a bit counter-intuitive (and can lead to bugs when you don't know this and rely on the order of notification, e.g. bug 606995), I think the g_object_notify and g_object_set[_property] (and gtk_container_child_set[_property] and gtk_widget_child_notify) docs should mention it.