Thunderbird 17 due for release on/around November 20th features a redesigned user interface. Like Firefox, Thunderbird is going to have a cleaner and simpler user interface. This means by default removing the Menu bar (which can be brought back temporarily via the ALT key and restored by going to View > Toolbars > Menu Bar) and using an App Button/Menu like Firefox. However, unlike Firefox it is not a ‘Thunderbird’ button and it is not at the top left. Instead it is a little button with 3 horizontal lines on the far right (yet another design ‘borrowed’ from Chrome which uses a similar icon in place on the ‘wrench’ button).
Like Firefox, when you click on the button you will get an app or quick menu. Like the other toolbar buttons, this button can be moved anywhere on to any of the toolbars via right-clicking on a toolbar and selecting Customize… then clicking and dragging the button. Also note that the screenshots here are using the default theme.
Personas Themes still work though I found that buttons placed in the Mail Toolbar will not retain their original colors, however placing these buttons on the Tab Bar will preserve their original appearance. Still no ‘Tabs on top’ menu option, but Rise of the Tools add-on does work in Thunderbird 17.
While it is nice to see Thunderbird go to a simpler user interface and the addition of the app menu like Firefox, I am rather disappointed with the way it was implemented. I would have preferred to see a ‘Thunderbird’ button which could combined with an add-on (such as Firefox’s Movable Firefox button that changes the ‘Firefox’ button into the Firefox logo and can be moved anywhere). I also think it is going to be confusing to users at first who would be expecting a button on the left side (like Firefox) instead of the right-side (as is the case in Chrome).