Ok.. lemme rephrase:
I have my macbook screen (scrn a) and an external screen (scrn b). Scrn B is connected to my macbook via miniDVI-DVI. I have scrn B setup as the "main screen". 2 days ago I could right click on scrn B and choose "change desktop background" and two windows would pop up on both screens depicting the desktop wallpaper options I had. I COULD choose a background on both windows which would only affect that screen. Now, when I use the scrn B's (main screen) desktop window, whatever I choose in it changes both screens backgrounds. But when I use the macbooks window it only changes the macbooks screen. it used to not do this. ANY help will be greatly appreciated.. hopefully i made it more clear now. 🙂
I still dont know where to find that file the other user suggested. 🙁