During the gutting of ClutterBox, the destroy and dispose implementation
were removed. The former, especially, destroyed all children - which
usually meant that the redraw queues for the childre was cleared as
well. The removal introduced crashes when a Box was destroyed while its
children were still queueing redraws.
This will make things interesting.
We have better replacements in ClutterActor, that do The Right Thing™
instead of deferring control and requiring reimplementation in every
single container actor.
ClutterBox functionality has been implemented by ClutterActor, and
proxied by the Box subclass; with the removal of the abstract bit on
ClutterActor, we can safely deprecated ClutterBox.
