Since this is not possible currently in combo with the "see only assigned tickets" option you have 2 chances currently:- Modify the source code, so they can see closed tickets as well- Create several own internal department which the agent then have full access to and then tell the agent to transfer the ticket to that internal department before he/she closes the ticket - so the agent can still see the tickets he/she closed since only he/she has access to one of these departments. Sure, this would require maybe a lot departments (one for each agent) but it would survive an upgrade of osTicket.