I'm also having trouble with Gmail - regular, not Apps for Domains. I'm using Firefox 3.0 on all systems.
0.50 works fine on Ubuntu 8.04, but on both Win XP Pro and Vista, I get none of the buttons in the Gmail interface. As with gbcox, it works properly for me when I go to the older interface.
Additionally, when I look at encrypted messages in other apps (SquirrelMail, for instance) I see the new inline PGP handler... the "display original" link works fine, but the "decrypt message" link produces no response.
Inline very cool, btw... now maybe I can get some Yahoo-using friends to start using GPG.
- Alex