I have a 2 display system on which I have moved the menu bar from the first display to the second, making the second display the main. When running pixel tests on this machine, most fail. It looks like what is happening is that the color profile is still being changed on display 1 while the tests are being run on display 2. This is a Mac Pro running 10.5.4 with ATI Radeon HD 2600 graphics, with 20" and 23" Cinema Displays connected.