I may have just not noticed this before - but I've been doing a lot of graphics work lately that envolves reference images that are in black and white - and I notice that whenever I switch windows that I can still see the reference image as if it's "burnt" into the screen. Gradually it fades. Is this usual, or is this a sign my display is dying? It's almost a year old. It's the 2001FPW from dell.