OTRS Only tickets are shown in queues where agents have "rw" permission

OTRS - Hat ein Benutzer nur Leserechte (ro) auf eine Queue werden keine Tickets angezeigt
user with readonly (RO) permissions can find tickets, but can't see tickets by default in AgentQueueView because tickets are not listed.
To resolve the issue search in SysConfig for ViewAllPossibleTickets and set 

Ticket::Frontend::AgentTicketQueue###ViewAllPossibleTickets to Yes.

$Self->{'Ticket::Frontend::AgentTicketQueue'}->{'ViewAllPossibleTickets'} =  '1';

Enjoy!