To resolve this behavior, follow these steps:

  1. Go to Start > Control Panel and double click on the mouse icon.
  2. Go to the “Pointer Options' tab and uncheck 'Automatically move pointer to the default button in a dialog box'.
  3. Click OK.


Background:
This behavior occurs due to a setting in Windows XP that automatically moves the mouse point to the default position when in a dialog box. The problem can be addressed by turning off this option.