Enable to find Subsite in the Navigation options after moving it

Let's assume I have the following structure :

 - Root Site
  - Subsite A  
     - Subsite A.1
     - Subsite A.2
  - Subsite B
  - Subsite C

I moved Subsite A.1 under Root Site so the structure became :

 - Root Site
  - Subsite A  
      - Subsite A.2
  - Subsite A.1
  - Subsite B
  - Subsite C

After this action, when i go to the navigation settings of the Root Site, I dont't see the Subsite A.1 (Under Structural Navigation: Editing and Sorting).

I want to put the Subsite A.1 at the same level of A, B and C but i want to hide it from the navigation of the root site. I am not able to hide it from the navigation setting, it is not visible.

I verified in the Structure and Content of the Root Site, and the Subsite A.1 have been mooved well and is under the Root Site now.