There are several situations in Security Manager when editor for managing users accounts is not available. In these cases a message explaining why the editor cannot be displayed is shown on its place. Here are the messages:
No connection is selected, and there are no objects in the user, role, or profile list (i.e. there is no user, role, or profile to select).
User has no rights to read security metadata.
If different types of objects are selected in the tree.