Just fixed an embarrassing error in my XHTML generator. Read on for details.
Someone was kind enough to point out that my code looked like an absolute disaster on early versions of FireFox.
It turns out that I had been inconsistent with the widths I had specified for my navigation bars. One piece of XSLT code was marking them as 150px wide, while another piece of CSS was saying 180px.
Unfortunately, both the version of Firefox on my own machine and Internet Explorer gracefully handle the problem, using the wider width.
Fixed now - and I’ve learnt (again) the lesson about always test with multiple browsers.