I have just upgraded to 12.04 and I have HUD running for many applications apart from Firefox (v14.0) and Thunderbird. I know that this is not default behaviour for many programs, but I have searched around in internet and I see that other people with my distribution version, do have HUD in Firefox. In my case the normal Firefox menus appear, and no Firefox-relevant option shows up in HUD, when hitting the Alt key.
Does anybody know why is this and how can I solve it?
Edit: one the same Ubuntu computer, I used another user account, and I opened Firefox. HUD is working there. So it is a user specific setting