That is exactly what i am doing right now. And i have no problem if it has to stay that way. However I thought i might be helpful for everyone extending CompoundPropertyModel, and given the fact that none of the methods in AttachedCompoundPropertyModel are final or otherwise protected against overriding i though it was an oversight. And like you said there is not much going on in that class so why not make it extendable.
Well, exactly because there isn't much going on in that class: why make expose it? It will only increase the API surface and limits our future options for refactoring the things internally. Eelco
