In the Music Explorer, when using "Sort by" a tag, then "Group by" another tag, you can (obviously) click on the "Sort by" result (in the above example, the list of <Sort Artist>s) and see the displayed albums, but when clicking on the "Group by" result ("Contemporary Hit" in the above), "No matches" are found. I think it'd be pretty cool if all the "Sort by" results could be displayed when selecting the "Group by" tag.
EDIT: This isn't a crucial request, but I was just playing around with the Music Explorer panel one day and discovered I wasn't able to get all the neat filter and count results with the above combination.