My wife wanted her website header image to be full-width with the body fixed at 900 pixels. By following the advice found in other threads, I managed to achieve that as you can see:
http://www.domni.com/TypeInsights2/

However, the header stays fixed in place when the user scrolls down. How can I make the background scroll in sync with the body?

Thanks,
Robin

The header image has a fixed attribute which I believe is causing your issue. What I would do is create a header image that was about 2000px wide to allow for a wide monitor I and use the following for the background image in ATO>Body, Text & Links. I have attached a modified header image as an example which you could use if you like.

background: #6666CC url(http://www.domni.com/TypeInsights2/images/SH2000x160.jpg) no-repeat top center;

You of course would have to take out your other background image code.

Thanks, lmilesw -- that gave me the nudge I needed.

I've fixed it now -- looks good!

(And, most importantly, my wife's happy with it...)