Issue when move a folder under its child

It is possible to move a older under its child folder which cause a disappearing of the folders between the initial place of the parent folder and the child.
This is caused because because the MBP folder structure is a Drupal vocabulary but in Drupal vocabularies this operation is disallowed (moving a parent under its child).

Step to reproduce:
1. Create children of the Media root.
2. Go to edit form of the Media root folder
3. Now the user is able to move the folder under his children - this is wrong!
4. Select one of the Media root children
5. And you will notice how some of the folder will disappeared.