Hello vintec ,
i have a solution for you
My OSTicket:
osTicket Version v1.9.14Web Server Software Apache/2.4.10 (Debian)MySQL Version 5.5.50PHP Version 5.6.24-0+deb8u1
1. Create a new column in Tabelle: ost_Groups
see 01
2. Edit class.group.php
see 02
3. Edit class.nav.php
see 03
4. Edit class.staff.php
see 04
5. Edit group.inc.php
see 05
6. Set permission with user tab
see 06
7. Set permission with out user tab
see 07
8. with permission "user tab" (admin)
see 08
9. Wthout permission "user tab" (noadmin)
see 09