Are you relying on WinIE's broken CSS to get a particular visual effect?
Floated elements (<li> in your case) should be removed from normal flow,
so they shouldn't affect the container (<ul> or <div>) height. One
solution is to not use list markup. IMO it isn't necessarily warranted
here anyway. Regardless, how to deal with float containers has been
posted many, many times. You could probably find the answer in the
google archives within a few minutes. Hint: "clear:both".
BTW, the blue boxes aren't the only area with overflow trouble. Neither
the boxes next to it nor the DHTML menus adjust with text size either.
Oh, and the page looks quite awful with JavaScript disabled, but then I
get some error with JS enabled so it seems that it is a lose-lose
situation.
As for MacIE, it has quite buggy overflow handling, as well as quirky
floats. How to get this layout to "work" in MacIE may not be so easy as
simply adjusting a width (or whatever). However, if you stop depending
on particular font sizes and pixel-precision for layout, you might get
better results. But then, people have been telling you this for a long
time now. Here's that link again, in case you've lost it
<URL:
http://www.allmyfaqs.com/faq.pl?AnySizeDesign>