Hierachrical Category
I would like to be able to mark a single category as hierarchical. This would make the category and its direct child categories appear in a navigation widget.
If any of its children are parents of each other, then a message should display that the action is not possible because of this conflict.
If a category is marked as hierarchical and someone tries to add a conflicting parent to any of these, then this should not be possible and give an error message to the user.