How to set quickslots for gamepad?

Hi, I’ve been trying to get a controller working with GD. The model I have is an 8bitDo Pro-2, although I suspect I’d have the same problems with other ones. The game seems to support it and I can access the page where I set up key mappings. Some things work like moving around, adjusting camera angles and firing default weapons. But I can’t figure out how to map any of the Quickbar slot keys. The controller set-up lists things called Action Bar 1, Action Bar 2 etc but I’m not sure if they are the same as the Quickbar keys. They are supposedly assigned to some of the keys but nothing happens when I press them.

In the in-game keybinding screen , it does list my controller keys as alternatives to the keyboard keys but they don’t work. Has anyone had any experience of setting up controllers who could help?