I think macfixit only displays the articles for a couple of days, so here is an excerpt:
"Erratic trackpads (#4): 2005 PowerBook G4 models
We continue to cover reports of erratic trackpad behavior on new (2005) PowerBook G4 computers. The most common complaint is an inconsistent issue where the mouse cursor will "jump" around the screen, apparently randomly. Several MacFixIt readers have noted that disabling the Clicking features in the Trackpad pane of Keyboard & Mouse preferences has proven to be a successful workaround. Reader Rich Snyder notes that installing an alternate trackpad driver, such as iScroll, has also helped:
"The symptoms i was seeing was that while typing, the cursor would randomly jump around the screen sometimes highlighting what I had just typed and the deleting it when I hit the next key. Very frustrating when you're typing a long response to a post on a forum and 'poof' its gone. To fix the erratic trackpad, I turned off Use trackpad for 'Clicking' and installed iScroll2. My iBook is now again fun to use. I never really used the trackpad for clicking. As a plus, iScroll2 gives the two finger trackpad functionality of the new powerbooks."
Confirmation of directional speed differences Yesterday we covered a reader report that the trackpad on the new PowerBooks -- which is made by a different vendor than past PowerBook and iBook trackpads -- seems to have a faster horizontal tracking speed than vertical. We've since received follow-ups from a number of readers confirming this behavior. Reader LLD notes:
"I can absolutely confirm that my new PowerBook trackpad behaves just like Chris [from yesterday's article] describes: moving my finger a certain distance on the trackpad horizontally results in a much faster track on the screen compared to moving the same distance vertically on the trackpad. Just something to get used to. No complaints otherwise!"
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neye: 
