Just a short post with a word of warning to Mac OS X Leopard users having the HTML Validator add-on – it might also apply to other Mac users.
I just installed the 0.8.4 version, which adds serial parsing and validating (W3C and Tidy) to the Mac; this has been available some time for PC and Linux users, and finally it was Mac users turn as well. However, Firefox completely hangs for me, the address field isn’t updated, the Back and Forward buttons stop working etc.
So, my advice is to not install this update until it’s more stable. If you already have, and experience the same mess as I do, older versions are also available for download.
Also, if anyone knows how to get it to work friendly with Firefox, let me know!
Just as Anthony suggested, getting the proper version manually seems to work just fine.