"Scroll Left" go to User Script:

mouseDown.target.scrollLeft += 60;
var result = { repeat: true };
result;

and then go to 'other gestures' enable wheel gestures, scroll UP -> 'your user script'

"Scroll Right" same as above but -=60 or whatever number of pixels you want scroll.

Dear developer. Your extension looks good, but could you please add ''Scroll Left'' and ''Scroll Right'' commands? I have a mouse with two additional buttons on its side, so I wanted to use these buttons to scroll web pages left or right.

Super!

aok

Ist echt cool. Macht genau was es soll. Sehr empfehlenswert.