I would love a collapsible menu! This would make it less confusing for my users who currently have to worm their way through multiple menus. Maybe at the bottom of a view in UX - Views, you could have an option like “Menu or Sub-Menu?” and then if you click “Sub-Menu”, it asks which Menu to attach it to.
This has been mentioned in another topic, but I figured I would add a feature request for a collapsable menu. @tsuji_koichi @Fabian @Nathan_Aycock
Thanks!