Bug: Unable to edit user's role membership via the 'Edit User' dialog box in ArcGIS Server Manager 10.2
When the server security settings are configured to use a Windows user store and ArcGIS for Server role store in ArcGIS Server Manager 10.2, the user is unable to edit a user's role membership via the ‘Edit User’ dialog box.
This is a known limit. At 10.2, the process of adding a user to a group does not complete.
Add users to groups using the 'Edit Roles’ dialog box. Do not use the 'Edit User’ dialog box.