My iBook G4 has an extremely annoying two-finger scroll. if i even touch it, it will zoom down to the bottom of the page. And if i scroll on it, it quickly jumps up and down from bottom to top. I am now forced to be less convenient and use other means of scrolling . I can seem to remember a time when this worked well, and i'm pretty sure it did at some point. Is there a way to fix this/make it normal?