I have a Macbook + 1 external monitor. I'm running OS X 10.6. I don't have any special calibration tools, but I have calibrated my external monitor to roughly match the colors and brightness of my Macbook's monitor. Normally, applications/pictures etc dragged from one screen to the other look approximately the same. Before yesterday, I was still using Firefox 3.6 which, like Chrome and Safari, looked the same on both monitors. Now I've upgraded to Firefox 5 which looks horribly washed-out on my external monitor. I think it's somehow messing with color profiles because there's a distinct point during the move between monitors at which its color and brightness change. I don't mean simply that the images displayed in the browser are somewhat different. I mean the Firefox UI itself changes. Please take a look at the full-screen recording of what I mean: http://optimizationbureau.com/color_change.mov (warning: 1280x800). Thanks.