I couldn't decide if this was hardware or software, but I imagine it could be solved by software so I'll put it in here. I have a Logitech MX900 mouse which doesn't have any OS X drivers but works magnificently nonetheless. It has scroll buttons on either side of the wheel. In 10.3 they worked properly: pressing them scrolled. In 10.4 however, it doesn't work so nicely. Pressing the button scrolls the window one "unit", and then displays the Cmd+Tab task switcher thing. But it stays on. As if I was HOLDING DOWN Cmd. Has anyone else had this problem? Is there any hope that I can put it back to normal without having drivers to work with?