The most irritating thing about using Firefox on Suse and is having the horizontal scroll act as back and forward keys.
The linked page gives a great insight into configuring Xorg.conf to take advantage of the numberous controls and button emulations a laptop touchpad provides.
But it also highlights the solution to the problem of horizontal scroll in firefox isn’t to disable horizontal scroll, rather tell firefox you don’t want it to behave that way.
In short, go to about:config in firefox.
Set mousewheel.horizscroll.withnokey.action to 0
Set mousewheel.horizscroll.withnokey.sysnumlines to true
Holding a modifier, like alt, control, meta (windows), or shift is still configured to perform back and forth.
If you want to know what other options are available see