Since the "internal" state is global, it will leak onto actors that you
didn't intend for it to, because it applies not just to the actors you
create, but also to any actors *they* create. Eg, if you have a dialog
box class, you might push/pop_internal around creating its buttons, so
that those buttons get marked as internal to the dialog box. But
ctx->internal_child will still be set during the *button*'s constructor
as well, and so, eg, the label and icon inside the button actor will
*also* be marked as internal children, even if that isn't what the
button class wanted.
The least intrusive change at this point is to make push_internal() and
pop_internal() two methods of the Actor class, and take a ClutterActor
pointer as the argument - thus moving the locality of the internal_child
counter to the Actor itself.
http://bugzilla.openedhand.com/show_bug.cgi?id=1990
