The product: handler is not currently aware of the product hierarchy. That's to say, if it is used to refer to a product resource it will only ever look in the product that it is asked to, it will not look in the parent products. Any code which expects to use the product: classhandler has to be coded to specifically know that it (rather than the handler) must walk up the tree.

Enhancing it to be aware of parent products, and to seamlessly search for resource there, would simplify the system and make the handler considerably more useful.