I know you can do these things programmatically, but a couple of clients have wanted to filter the view in Backstage by a collection's category (Association). It would be nice if there was a Wordpress-style filter drop-down for this.
I'm not too familiar with what Wordpress does, but I can kind of imagine something like what Excel does with Autofilter. Can you privately email me the URL of the page they'd want to filter so I can see what they've got going on there?