Tabs on top is scheduled to land in Thunderbird 11, and we’re pretty excited.
A few folks on Bugzilla have been wondering about how they can switch back to Tabs on Bottom, and have been shocked to find that such a toggle is missing. A bug was filed by a concerned user, asking us to put the toggle in. They were concerned that we were restricting customization and flexibility by not allowing them to change the tabs UI.
However, this lack of a toggle was a conscious decision, and was not made lightly.
I gave our reasoning in the bug, and I thought I’d include a copy here as well. Here goes:
So I’m going to talk a bit about the decision to move tabs in Thunderbird above the mail toolbar - and, more specifically, the decision to leave the UI toggle to move the tabs back to below the toolbar out.
When it comes to UI stuff, I can get pretty hand-wave-y and long-winded. In a departure from this, I’m going to try to be succinct here - please don’t interpret this as rudeness or brusqueness! :D
In Firefox, you have a back button, a forward button, and a URL bar to tell you where you are. With these rudimentary tools, the toolbar is easily generalizable to the act of navigation. This works for Firefox, because this is what Firefox *is* - a tool for navigating around the web. A high percentage of the things that you can do in Firefox involve navigation. Even in the Add-ons Manager, or Bookmarks Manager, the browser toolbar could make sense as a navigation interface (though we don’t seem to make those available - in fact, in the Add-ons Manager, we’ve created *new* back and forward buttons for navigation).
Where the browser toolbar *doesn’t* make sense, is in a place where navigation has less meaning. I’m going to pick on the Downloads Manager, for example. Firefox does not have the browser toolbar as part of the Downloads Manager, and outside of an add-on, such a customization is not really possible.
The reasoning behind this is obvious - having a back/forward/URL tools in the Downloads Manager makes very little sense.
So, the conclusion we can draw from this is: a shared toolbar makes sense in contexts that share the primary activity of that toolbar. This is why Firefox can get away with tabs-on-bottom for most of their UI.
Now, on to Thunderbird.
The rationale behind tabs-on-top in Thunderbird is somewhat different from Firefox’s. In Thunderbird, a tab can be many other things than just another Inbox tab.
Lightning, for example, gives us a tab that becomes a full-blown Calendering client. Unfortunately, they’ve had to deal with tabs-on-bottom, and have therefore been forced to shoehorn Calendering UI into the mail toolbar. If you’ve used Lightning, you know what I’m talking about.
This is not unique to Lightning. When viewing a content tab in Thunderbird, the mail toolbar above the content really makes very little sense - just like having the browser navigation bar in the Downloads Manager would make very little sense.
This is also quite restrictive. Thunderbird’s UI trajectory is tending towards more tab types (Search, Instant Messaging, eventually Compose in a tab, eventually Address Book in a tab). Having the toolbar exist *within* the tabs allows us a separation between these functions - and allows for a greater degree of customization *within* those tabs.
So I don’t think it’s fair to say that preventing tabs-on-bottom is making Thunderbird less configurable. On the contrary, I suggest that enforcing tabs-on-top is an investment that *ensures* greater flexibility and customization in the future.
All the best,