George's post here caused me to notice this problem.
Currently there is no easy way to do morphological searches in collections. We cannot select a collection from the morph search menu, and the normal morphological search syntax doesn't work in the Bible menu.
It would be nice to either be able to search collections from the morphological search menu or use normal morphological search syntax (lemma:word@etc) in the Bible search menu. I'd prefer option number one.