[otrs] User permission

Good day, I am having problem with user permission, I have set agent permission to a group as follows; ro - yes move_into - yes create - yes owner - no priority - no rw - yes After submitting, the ownership and priority change to yes. How do i ensure that the agent doesn't have the permission to change the ownership. The agent should be able to read and update ticket, move ticket into queue and finally create it. I tried a couple of time to change it but doesn't seem to work. Pls help. Thanks, Fairuz