I searched for a discussion to give myself answers, but couldn't find one. I have a 15" PB w/ a 23" Cinema Display connected. I set up the "wallpaper" for each screen's desktop. Things looked fine. Then today, I was working away - didn't do anything too unusual - lots of web-surfing via Safari and downloaded some stuff, too. Then I tried to change the "wallpaper" for each display's desktop, and ran into problems on the 23" CD. First, I tried to change it to some of the "Solid Colors", but no matter which color swatch I choose, the display only shows that medium blue color. Also, when I try to pick any of the Apple "Nature" pics in widescreen format (ladybug, dewdrop, sand dunes, etc.), the nature picture does not fill up the whole 23" screen - it looks more like it's stretched to fit a 15" or 17" PB-aspect ration display. I had used these nature pics before for the 23" and before, they stretched out fine. When I choose a wallpaper that I downloaded myself, a 1900x1200 pic, it is fine - it stretches to fit the screen snugly. I've restarted a few times and disconnected/reconnected the CD, but this problem still persists. I've also told it to "detect displays" to see if that would help reset/fix anything, but it didn't. I don't seem to be having similar problems w/ getting the color/picture I want, and for it to fit normally, on the 15" PB. I called Apple support, but they are closed right now! Hope someone has the answer - thanks.