Grading a complete/incomplete assignment currently requires two clicks (once on the combo box, once on "complete", "incomplete", or "excused"). This unnecessarily slows down grading and increases potential misclicks.
Displaying three buttons ("complete", "incomplete", and "excused") instead of the combo box reduces the required clicks in half, increasing grading speed and reducing one option for mis-clicks. The currently selected grade would need to be indicated (such as by bolding the text) when revisiting the assignment.
