I've noticed something strange with CompositeElement - unlike proxy element, which sets container to proxied element, this one does not send any container-related notifications to children. This breaks long element trees, like it breaks MASTNew plugin (I'm debugging it right now, trying to make click throughs work - they don't, at least they don't with OpenX VAST). My idea is that CompositeElement should probably send ContainerChangeEvent.CONTAINER_CHANGE to all children when they added, or when element's container changes. This kinda makes sense, but I don't see this even in the recent commits. What do you, guys, think?