Be careful with old versions!
These versions are displayed for reference and testing purposes. You should always use the latest version of an add-on.
Note that having the tabs between the titlebar and the toolbar is a change in Thunderbird, that follows a new idea here. There is some sense in putting the toolbar under the tabs (there is no need for the menu bar, through, so I let it on top), so you can go with this theme even if you want the new concept.
If you want to stick to the old concept, get Rise of the Tools.
Fixed glitch with HTML editing.