I have coded myself into a CSS corner. Have a look at this page:
http://staging.jungledragon.com/image/1082/sizes/large
Open this page and make sure the width of your browser window is smaller than the total width of the content, so that a horizontal scrollbar appears. If you now scroll to the right, you will notice that both the header and footer are broken, the reason being that they are set to 100%. 100% means the width of the viewport, not the browser window itself.
In my search for a solution, this one pops up a lot:
http://www.springload.co.nz/love-the-web/backgrounds-disappear-on-horizontal-scroll/
This is no solution for me since I do not know in advance how wide my footer and header need to be. Also, I cannot simply set it to a very high min width value since that would always trigger scrollbars, even when they are not needed.
How can I extend my headers and footers to the size of the actual browser window, whilst still getting proper horizonal scrollbar behavior. Is it possible at all?