it is surprising if the repository strategy does not work in this case. but i can live with that if the alternative is a big messup that affects everything else. we then just have to make people understand what the proper way to add a named child to the collection is. is adding to the collection always ignoring the repository strategy, or only in the case of merge?

but unless i am really confused, the test as i wrote it has the side effect of preventing the removal of the old child-a so there is some mixup/sideffect.