![Laughing :lol:](./images/smilies/icon_lol.gif)
Third mouse button is just wired to the matrix as an additional key. And you can scroll with it like on a thinkpad.
I will try to bring the sketch and matrix documentation to some readable state to post it, but can't promise how soon.
i found that the keys are now a little bit to small to be comfortable, and i often had troubles not pressing the left/right one by accident