#1 Support non-recursive copies in the tree-views

[Charles Schmidt]

Right now, only recursive copies are allowed due to paste or drag-drop. This is because, for a non-recursive copy to occur, we would need to check other fields to ensure the different structure of the copied element was allowed by the schema. Specifically, a child element could be required by the parent's schema and not including it could violate the schema. As such, this feature has not yet been included.