I have set up a new Stash test instance. One of the first things I've done is to set up Crowd as the user directory and to disabled the internal directory.

As Crowd is read-only (and will always be read-only from Stash's point of view), the "Add Users" box on the dashboard has no purpose and would potentially lead to confusion as local group/user management is not possible from Stash. Clicking on the link brings the user to Stash's admin page, but it probably should just be hidden.

Additionally, when viewing a group (see screenshot), the Add Users link exists but the only directory available (crowd) is read-only and so no changes can actually be made.