When all submissions are in marking-status "marked" the instructor can release marks, so that students can view marks for their submissions. Also, he/she can unrelease marks. Once marks have been released, they cannot be changed. In order to change marks upon release the instructor has to unrelease marks first.
* Test if Graders can change marks when submissions for an assignment are released.
* Should the instructor be able to release marks before all submissions are in "marked" status?