Wonder how difficult it would be to add an extra option on a single button. Say sort is a clickable button that will sort upon command but you can descend within that menu with options like advanced sort settings, search for specific item, save/load sort, and undo.

Example is like right clicking on your desktop you get a basic menu (as you would right clicking on an item) and then you can go to "sort by" and get more options, but in this case the "sort by" button itself would be "sort" a left clickable action while perhaps a right click would show you the nested menu. Probably not a feature to be added in a few minutes, maybe a lot of work - though I'd be a little disappointed if it wasn't a feature-able possibility given they are trying to bring addon support.