1) we removed the category nodes in the meanwhile
2) no need to invoke after the update controller; I changed the order index and added a comment
3) yes, on add or remove, we set the ADDED or REMOVED properties, so the flags are updated
4) deleting a newly added node is not treated at the moment; when we implement the veto system for controllers, then we'll have the CSRemoveNodeController not prevent the persistence controller from removing a node if it was marked as added