When you set a gradable task, you need to be able to state its Category for grouping in the Grade book. At the moment, you can only assign categories in the grade book itself. Maybe the label Category in the Quiz itself and a different category in the Gradebook is confusing.
It would also be helpful if you could assign more than one category to each gradable task - something likes the TAGS of Web2
Could it be possible to state that I am currently working with a certain Category of tests and a particular group of students? Having to select and both and sort results every time you return to the page is extremely time consuming.