When I was a poor graduate student, I wanted to get a Kensington trackball(right) for my Mac. However, the price was way too high for my budget and I settled for a cheaper trackball. Eventually, I forgot about the Kensington when I bought a Microsoft trackball. While people are supposed to loath Microsoft, I found the trackball to be almost perfect for me. Then it finally wore out and I got another one. When that one wore out I found that Microsoft no longer made them. I looked on Amazon and saw that I could get one for a few hundred dollars. While I loved the trackball, I was not in love with it and hence decided to pass.
Looking for a good replacement, I remembered the Kensington. I saw that the Expert Mouse (which is actually a trackball and not a mouse) was on sale at Amazon, so I got one. When it arrived, I installed the software and was prepared for it to live up to the glowing reviews I had read. However, my experience was horrible. The scroll ring seemed incapable of actually scrolling-I would move it and the scroll bars would go up or down seemingly at random. When I clicked on the lower left hand button (set for a single click) it would cause the scroll bars to move and would also sometimes “jump” to other fields. For example, when trying to blog in WordPress it would scroll the main text area, then the categories would suddenly start scrolling up and down. The same sort of thing happened in the Start Menu: I would try to click on a program icon but the click would cause the scroll bars to move up or down randomly instead.
I was not happy and was ready to send the mouse back.
However, I realized that the problems seemed like the mouse was somehow getting two sets of signals and seemed “confused.” I suspected that perhaps the custom Kensington software was somehow at odds with the standard mouse software. To test this, I uninstalled the Kensington software and the problem was solved: the scroll wheel worked flawlessly and the scroll-click problem had ceased.
So, if you run into this problem, uninstall the software. If you want to custom configure the trackball, you can install the software and then remove it after setting the preferences. Interestingly, the button assignments I did using the Kensington software stayed even after I uninstalled the software.
Overall, I really like the Expert Mouse. However, many people are not fond of trackballs, so be sure to give it a try before you buy. Assuming, of course, anyone still goes to a store to buy mice/trackballs.