The Mouse preference pane option to "Ignore trackpad when mouse is present" for PowerBooks and iBooks may not work when non-Apple mice or newer models of Apple mice are connected to the computer.
Symptom
The trackpad continues to work even though the "Ignore trackpad when mouse is present" option is enabled and a mouse is connected.
Solution
If you are using a third-party mouse and have installed software for it, the driver may not recognize this setting in the Mouse preference pane. In these cases you should contact the vendor of the mouse.
If you are using a later model Apple Pro Mouse (including all white optical mice and black optical mice with white cables), this setting may not work. If available, you can use an earlier Apple mouse to avoid the issue.