When I am in the list of messages in Yahoo' New Mail, the scroll wheel does not properly scroll through the messages. It barely moves at all (maybe one line with five scrolls). Scrolling seems to work fine in all other parts of the browser. I have this same problem in Chrome 4.0.288.1dev and Firefox 3.5.7, and IE 8.
I have checked the scroll settings and tried selecting the highest scroll rate and the advanced setting to increase speed when scrolling faster. This has not changed the performance at all.
This problem is new since upgrading from XP to Windows 7 Ultimate and reinstalling the mouse driver.
I have another laptop, no external mouse or keyboard, Windows 7, and there is no problem with the scrolling (using it's touchpad, so I assume it has something to do with the Intellipoint software.