If I have a link in the clipboard, anytime I scroll down with the touchpad there is a chance for Firefox to unexpectedly follow the link. But it's totally random. This is a problem, because it usually happens when I'm reading something and I have to go back and try to find what I was reading.
OS : Ubuntu 12.4.1
Windows : GNOME Fallback (Gnome 3 "Classic", with menu bar - no Shell)