If you click on any drop down on natty in Thunderbird 13/13.0.1, the drop down doesn't appear. We fixed a similar issue in bug 1010466 for oneiric and precise. We pushed a fix out for natty as well, but it appears to be incomplete. You can test the updated thunderbird packages from ppa:ubuntu-mozilla-security/ppa
Test case:
1. Edit -> Account Settings
2. Click on account actions, it should show a drop down of choices, but doesn't
If you click on any drop down on natty in Thunderbird 13/13.0.1, the drop down doesn't appear. We fixed a similar issue in bug 1010466 for oneiric and precise. We pushed a fix out for natty as well, but it appears to be incomplete. You can test the updated thunderbird packages from ppa:ubuntu- mozilla- security/ ppa
Test case:
1. Edit -> Account Settings
2. Click on account actions, it should show a drop down of choices, but doesn't