If an actor is (unfortunately) queuing a relayout in relayout, you would
end up with (ClutterActor*)stage->needs_allocation set to TRUE and
stage->relayout_pending set to TRUE. But if then in the same cycle, an
actor calls clutter_actor_get_allocation_box, that will trigger another
(recursive) _clutter_stage_maybe_relayout, which will wrongly reset the
relayout pending to FALSE, while not actually performing a new relayout
because of the re-entrancy protection.
http://bugzilla.clutter-project.org/show_bug.cgi?id=2503
c95cc8d477