Here is a bit of shell script which makes it possible to use my Kensington Expert Wireless Trackball Mouse under X11:
xinput --set-button-map "$nm" 1 8 3 4 5 6 7 2 xinput --set-prop --type=int --format=8 "$nm" \ 'libinput Drag Lock Buttons' 2 1 The trackball is large, it sits in one place, and unless I can make one of the buttons be a drag lock button, it is almost impossible to use, needing to cross over both hands or play twister with my fingers :-). (If I can use drag lock, it is the best mouse I've ever had). Is there any way at all to do this in wayland? I recently tried wayland on an ubuntu 20.04 system, and could not find anything like it. I'd be happy to buy a couple of trackballs for wayland developers if they'd promise to support drag lock :-). Alternatively, perhaps you could tell me where such support would best be implemented and I could see about implementing it myself. Shouldn't take me more than a year to come up to speed on the software :-).