Help Needed - How to Make Middle Mouse Button a Drag-Lock

[cerrec]

I have a genuine 3 button mouse - no scroll wheel. I want to make the middle button a drag-lock. In other words, it would be a left mouse click that sustains when you release your finger from the mouse. You could then drag things around without having to hold the button down. And to end the drag, you click the middle button again to release it. I'm a total noob and haven't a clue how to do this. If anybody could offer a solution that actually works, that would be great. BTW, the reason I want to do this is to mitigate carpal tunnel problems. Thanks!

[paddlepaw]

This worked for me.

if_eq($draglock, 0, key_down(BTN_MIDDLE).set(draglock,1),key_up(BTN_MIDDLE).set(draglock,0))

Note: there is a slight delay, at least for me, after you press the middle button, before the drag lock is enabled.
Source: https://silvester.org.uk/2024/07/01/setting-up-custom-buttons-and-scrolling-for-kensington-trackballs-under-linux-part-2-wayland-version/