I started to use Thunderbird3b1 in order to study feasibility of updating my extensions for Thunderbird3. for Thunderbird3b1
- Open a selected message in a tab by a toolbar button
- Open a message in a tab by double-clicking it when the toolbar button's dropdown menu is checked
- Open a selected message in a tab by Shift+T shortcut key
BTW, I read some codes of Thunderbird3b1 and I seems that alomost all my extensions will not work on Thunderbird3. I'm going to start to update them for Thunderbird3 after Thunderbird3b2 release but some of them may not be updated in time for Thunderbird3.0 release.