I upgraded to FireFox v3.6 on Windows XP Home Edition with latest O/S updates. I can't recall the exact prior version of FF but it was 3.x (def not 3.5).
Since the upgrade, PWM has not correctly identified URLs with 2nd level domains.
For example, when generating a password for
www.amazon.co.uk, instead of automatically using text 'amazon.co.uk' it is now using text 'co.uk'.