What's the real problem when you're not wrapping? The side bar grows. Which devices use browsers that do not support CSS? I think most of them are devices with small screens, that can't render silly table based layouts correctly anyway. Others may be ancient browsers or text based browsers, but users who pick those are used to horizontal scrolling anyway, as table rendering improved much in the past few years.

I'm curious which specific supported user agent has a screen big enough to handle the big table layout of PM, but do not support CSS.

Or is Netscape 4 still supported? MSIE 3? Opera 5? In that case, I can only say that I think such a decision is a bad one, and express my sympathy for PM developers.