Regarding this issue:
When a member is provided with the queuemanager permission, everything works fine. When clicking on the presence of any member in the extensions window you can add the member to a queue. Once added to a queue, clicking on the presence icon shows the context menu to remove a member from the queue.
When a person gets given the queueagent permission, they can add themselves to a queue, however they can not remove themselves, as when they click on their own presence in the queue window, there is no context menu to do so.