But hasn't given me the answer. Just plugged in a mouse in 12.04 and there's no horizontal scrolling with the mousewheel. Instead it has strange behaviour where text is changed if mousewheel is held down and moved over it. HP mouse, feature works on windows 7.
I have solved this once in the past, it's just been so long I can't remember how, and can't find anything. My horizontal scrolling action is working in Kubuntu/KDE, as I can use horizontal scrolling where it's appropriate.