stylesheet located at www.cedarnet.org/demo/v5/standard.css The only percentage used in the stylesheet renders incorrectly. Works with Nav4 & IE5. Percentage used for positioning of layer from top as shown here: .footerbox { position: absolute; height: auto; width: 80px; top: 98%; left: 0px; z-index: 4;

CSS2, section 9.3.2 ( http://www.w3.org/TR/REC-CSS2/visuren.html#position-props ) says: <percentage> The offset is a percentage of the containing block's width (for 'left' or 'right') or height (for 'top' and 'bottom'). For 'top' and 'bottom', if the height of the containing block is not specified explicitly (i.e., it depends on content height), the percentage value is interpreted like 'auto'. Thus I think Mozilla is correct. If you want positioning relative to the viewport (which is how it seems) then you might want to use position:fixed.

Altering the stylesheet with a defined height for .footerbox makes no difference. I am confused when you say use position:fixed. I have not seen "fixed" before, only "static, absolute, relative" The code presented works in the older browsers of both sorts, I believe this is a bug that needs to be fixed for the sake of backward compatibility if it does not break the standard by doing so.

It's not .footerbox that needs a defined height, it's the "containing block" that needs it. Nav 4.5's behavior on this page is just plain wrong (top is based on window width, not height) and we'd break conformance with the CSS spec if we tried to mimic it.