Hi Jacky,
I have spent quite a long time to understand that the presentation of the changes that you do in the library views that can be seen by remotes like JRemote or Gizmo is not available at the time you click on OK.
This is typically a "feature" that was unforseen
I am using MC18 and may be it has been corrected in the newer versions.
You MUST close JRiver Media Server completely. I am not sure if you need to close your computer as well (some services might still be running and I do not know which ones)
In order to verify what you have done at the level of the presentation of the new library view, do as shown below:
With your web browser (on the computer itself !) go to the following adress :
http://localhost:52199/LibraryServer/If you see the new branch that you have created, you're OK
On your smartphone, maybe you will need to delete the content of the application cache.
Cheers,
Jacou