When grading manually graded quiz questions, I am unable to sort by the "Completed" date. Clicking on this header puts in place some sorting mechanism, but one that is NOT the actual completed date. Looking at the URL header, it appears that the attempts are being sorted by "attempt" and not by the date that the attempt was completed.
The reason that this is a problem is because my students finish quizzes at staggered times which means I review the attempts once or twice a week to manually grade the questions. If I know that there are, say, 4 ungraded questions (as reported in the list of ungraded questions), I know that these must be the four most recently completed. Without being able to accurately sort by this value, it becomes a long and involved process to find either the mosty recent 4 (I have resorted to cutting and pasting the complete table into Excel) or to click on the "Grade All" link and then finding the attempts with no comment.