Staff
There might still be demand for finer control on work item level, that allows the process initiator/owner/manager to define whom (s)he wants to be allowed to play a specific role for that specific item.
This feature is called staffing.
To enable staffing for items in a specific tracker, you must grant Permissions to the Staff field:
For example, only Project Admins should be allowed to edit the Staff:
The item's details screen, will then have an additional Staff tab, where you can see (and edit) which roles have been assigned dedicated members.
For example, A task Demonstrate Staff, where the role Developer is exclusively assigned to the user klaus and Tester to zoltan:
Staff members are a subset of the Project members in that role. Only individuals can be assigned, no roles.
For example, members of the Codebeamer project:
By assigning specific staff members, you implicitly revoke that role (in conjunction with this item) from all other project members in that role.
For example.:
• sandor, although he has the role Tester in the project, is not a Tester in respect of the task Demonstrate Staff.
In fact, he has no access to that task at all, because Tester was his only role.
• zoltan, although he is Developer and Tester in the project, loses his Developer role and only keeps Tester.
For all roles without explicit Staff assignments, the default project members in that role apply.
Using Staff gives you full control over the Flow of Responsibility, even if it is not you, that will have to assign the work item to specific workers in some later stage. But it is you, that controls, who can be assigned at all.