If you want to do automatic, you will need to make a change to some codes, I don't know too much about it, where they might be linked, but I found couple codes in\include\staff\ticket-view.inc.php line 738, 827 "$states = array_merge($states, array('closed'));"I assume you can change that to what you want, note I have NOT tested this if that works post it, so others know
