So following some tricky automation I found myself needing to ‘catch’ order quantity changes on the +/- buttons but that’s currently only possible through Ticket Total Changed event but that gave me other issues as was working with calculations.
Anyway.
Automation Commands
Plus Quantity
Minus Quantity
Both will want mapping to order line with visible state of New
Automation Command Executed Rule
You could get creative with order states to make minus disable on 1 quantity but opted just for action constraints.