Have you edited xorg.conf for your mouse? What mouse is it?
If so, type about:config in the address bar, look for mousewheel. And refer to this article at mozillazine for values to enter.
Look at this wiki as well. for possible xorg.conf changes you need to do for your mouse.
And these community documents found at ubuntu.com can also help.
Users browsing this forum: Bing [Bot] and 18 guests