I stumbled upon this quite by accident: all you need do is put the content you want scrolled inside a
nnis the height you want your content. The
trcontaining your headers goes outside this
tbody. This has been obvious all along to people who understand CSS, but I'm only starting to get to grips with this stuff. Here's an example, hit view source to see how it works:
It's not so pretty - the vertical scrollbar is visible only if you've scrolled horizontally all the way to the right. But given that you can scroll with the keyboard or mouse wheel, perhaps that's not such a terrible thing ...