Feature Request: Order of queryset when grading

In grading page, the order of flowsession queryset is the username of participants, that will make it hard to locate ungraded flow session, especially when there are newly submitted sessions. We will have to go back to grade book to find them. I made a select2 widget to select ungraded session, but that's not enough.

I think we can learn from the admin to save a preserved_filter in the url (when some field are ordered in by-opportunity page), and pass that order to the url grade-single page and consequently the grading page, so that we can use the query sting in the url to determine what order we would like to use. Or the simplest, just add an order choice in the grading page and reflect that choice in the url query string.