Hi Sofia!
The list is ordered first by Type then by Name, so if you have
mixed user types (eg. Extranet, Windows and LDap), the list can
appear somewhat random.
The list order is determined by the Order By statement in the
stored procedure 'netSidSearch'
If you decide to alter the ordering in the procedure, beware of
that future updates of EPiServer might overwrite your changes.
Best regards,
Johan Olofsson
EPiServer AB