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Thunderbird 115 Supernova Preview: The New Folder Pane

In our last blog post, we announced that we’re rebuilding the Thunderbird UI from scratch, with the first results coming to Thunderbird 115 “Supernova” this July. We also explained why it’s necessary to begin removing some technical and interface debt, and to modernize things in order to sustain the project for decades to come. That post may have caused you to worry that Thunderbird 115’s interface would be radically different and ship with less customization options. Perhaps fearful you’d have to relearn how to use the application.

Nothing could be further from the truth! In this post — and in future Supernova previews — we want to put all those worries to rest by showing you how Thunderbird 115 will be intuitive and welcoming to new users, while remaining familiar and comfortable for veteran users.

Product Design Manager Alex Castellani takes you on a guided tour of the new Thunderbird folder pane.

Today we’re going to take a look at the new Thunderbird folder pane. That’s the section on the left of the application that displays all of your mail accounts, feed accounts, chat accounts, and local folders.

Folder Pane: Thunderbird 102 vs Thunderbird 115

Here is what the folder pane looks right right now, in Thunderbird 102:

The Thunderbird folder pane in version 102, showing local folders, mail accounts, and subfolders.
Thunderbird 102 Folder Pane

Now, let’s see the new folder pane that’s coming in Thunderbird 115. Don’t worry, we’ll explain the new design and the new buttons further down.

Thunderbird 115 Folder Pane — with Unified Folder Mode and relaxed density

See how roomy and breathable that is? See all the white space that helps prevent cognitive overload? This will feel familiar to users who’ve only used webmail in the past.

Wait, wait! Before you get angry and close your browser tab, let’s take an additional look at the Thunderbird 115 folder pane, right next to the existing Thunderbird 102 folder pane:

Thunderbird 115 Folder Pane with Unified Folder Mode disabled and default density

Hmm, that looks identical to the current folder pane! What’s going on here? The above iteration of the Thunderbird 115 folder pane simply has Unified Folder mode turned off, and the density set to default instead of relaxed.

It’s exactly what you’re already used to!

Different People, Different Needs

We understand that many of you love the traditional, compact Thunderbird UI that presents much more information at a glance. We also know that many of our users dislike all that information being so cramped and squished together.

So, who’s right? Everyone is right! One of the benefits of rebuilding the Thunderbird interface from scratch is that we can better tailor the application to satisfy different people with different needs.

New Feature: The Folder Pane Header

Some users rely on the toolbar, shown just below, for their action buttons. That area near the top of Thunderbird has always been the default location for the main actions in your current tab.

The toolbar in Thunderbird 102

But others prefer to completely remove all buttons from the toolbar, and rely exclusively on the menu bar to access options and features. A different set of users might completely hide both the menu bar and toolbar and interact exclusively with shortcuts.

These situations are just a few examples of how different users like to change the interface to feel more productive. That’s why we’re planning to offer more easily discoverable contextual options for specific areas.

That’s where the new Folder Pane Header enters the picture:

Using a primary button to highlight the most important action in the current context (like writing a message) is a common UX paradigm that helps new users focus on simple, common actions.

Adding that button in the new folder pane makes it easily accessible for users that rely on assistive technologies, or who navigate exclusively with a keyboard.

In the same area, we added a button to fetch messages from the server. Just in case users want to force the syncing process.

On the right, an accessible “meatball” menu button will allow users to:

What if you don’t care about these new buttons and don’t want them? Are they just a waste of space in your workflow? You can simply hide the entire area with one click, and that preference will be remembered forever in your profile.

New Feature: Tags and Local Folder Options

Younger users have become used to using simpler interfaces. They’ve never used a “Local Folder” and probably don’t even know what that is. So, we’re offering a simple option to turn the Local Folders display on or off.

You might be familiar with Tags, which are basically labels that filter your email. Tags behave a lot like virtual folders. If you select a Tag, you end up with a subset of messages that have that tag, which simply looks at a folder with the same tag name.

We understand that some users might prefer having the Tags button in the toolbar, or not using tags at all. Meanwhile, others might rely heavily on tags. That’s why we’re adding the option to show them in the new folder pane.

As you’d expect, you’ll be able to re-order all these sections to suit your own preferences and workflows. And if nothing in this entire post appeals to you, rest assured that all of it is completely optional in Thunderbird 115!

For users who don’t consider the current Thunderbird interface comfortable, we’re confident these new features will make you feel right at home — with the added benefits Thunderbird brings compared to traditional webmail: privacy, customization, no ads, and absolutely no selling of your data.

Thunderbird 115 “Supernova” launches this July. A beta will be available for you to try by mid-April.

38 responses

CArsten wrote on

I kind of like it, but not sure if a unified approach will work on the desktop with quite a few different mail accounts (though it works quite nicely in mostly reading mode on Android K9).

Very much looking forward to v115 and beyond, still hopeful that performance will stay the same or will be better (I’m a mail hog with > 100k mails per box) and still have quick find and overall search. Tagging/starring emails seems to stay (good!!), hopefully S/MIME as well.

Please don’t break extensions :).

Will the calendar still be a part of T’s future?

Ezequiel wrote on

Can’t wait for its release. I hope they fix the “so much stuff on screen” problem that thunderbird currently has

Ade Malsasa Akbar wrote on

That’s very great. I want to use Supernova soon. Thanks for the nice information, Thunderbird.

Sincerely yours,


Joerg wrote on

Have been waiting for an option to sort my many accounts in the left bar for so long.

If thats possible in the new UI I will accept any other changes.

Jason Evangelho wrote on

It’s possible right now in Thunderbird 102! Check out this short video:

George E. wrote on

Looks great! Can’t wait for the beta to be honest. As long as my Dark Reader still works (or there’s a built-in and functioning dark mode), and it still supports PGP & S/MIME I’m golden.

Cypher Jack wrote on

I am really happy to see Thunderbird getting a refreshed UI !

Boudreaux wrote on

It would be ideal if it weren’t an either/or –
I’d prefer to have (just) a unified INBOX, *plus* have each of my accounts separate

Stephen wrote on

And I am really happy that we who want an approach to the email client to remain usable as we have used it for decades in my case, decade and half now I think it was 2008 I started with it, will see the option to continue. I grow tired of having to abandon applications on my computer that think they are doing their users a favour by destroying the usability in their quest to chase the new shinny to become a web or cell phone application on my computer in their UI designs.

V R Govinda wrote on

Great news! It would be nice if:

1. We have a Dark mode out of box without the need for an external add-on like Dark reader etc..

2. The interface [with the folder pane, message list and the message pane in vertical columns] is compact and efficient in using the horizontal screen space while at the same time showing up all the message previews at a glance.

3. We have a ultra compact message header bar.

Hope I have communicated clearly.

Chris wrote on

Looking nice so far Thunderbird!

Anas wrote on

Very nice video introducing the ideas behind the changes.

Just one suggestion: the new message button can be simplified to just an icon. And folder modes can be made a first class option.

Robert Kaombe wrote on

Heading in the right direction. This is great.

Arctic Boar wrote on

I’ve only started using Thunderbird a few months ago to have a local copy of my GMail and also a local private archive of the emails and offload the clutter from GMail.

Seeing the new UI is quite refreshing and looking forward to these changes. Thank you for the great work.

Dealing with GMail has been quite hectic to archive properly and avoid duplication or label removal and then ending up inside All Mail.
I hope there can be an easier approach to this as a continuous sync/archive approach.

I created folder search rules to cut off after a specific year, then move these emails to trash, then copy them from GMail trash to a local folder.

If I can use tags instead of folders, it’d make my approach easier.

Abdullah Khalid wrote on

The graphical changes do seem more refreshing. Thanks for the work.

I hope the Unified view remains, as it would be very difficult for me to use TB without it.

I spend 95% of my time in TB working with one of my email inboxes (rather than Sent/Archives) etc. And Unified view, puts them as a list right at the top of the Folder Pane.

Jens wrote on

I need my diferent email accounts to remain separate in the tree. Will this be possible?

Jason Evangelho wrote on

Yes of course! It can remain the way you’re used to now. The Unified Mode is just an option.

Matthew wrote on

This is looking fantastic! I’m really liking the direction Thunderbird is going in – it’s still the same Thunderbird we know and love, but with a brand new coat of paint 😛

As someone who tends to use whatever “simple” built-in Mail and Calendar apps are on the platform, I like that the team is aiming for less visual and cognitive complexity. It’s resolving a lot of pain points I had when using Thunderbird in the past.

Is there any chance we could see a similar refresh coming to the Calendar view?

Also +1 for integrating the classic workflow too for long time users; it really is the best of both worlds.

Jason Evangelho wrote on

Hey Matthew! Yes, you’re going to see this same kind of refresh across the entire application! Here’s a quick look at the updated calendar UI, as of a couple months ago. Expect it to look much better at final release:

Anna Christina wrote on

It’s great that these changes remain optional and that it will be possible to make it look like before.
I hope that I can make it almost look like “Netscape Mail from 20 years ago + Lightning” as I’m doing it now 🙂

But most of all I hope that the new version completely adheres to the Gtk theme and the color scheme that I have configured in my Linux (ie. KDE) desktop (I’m looking at you, left pane with the mail/calendar/address book/… icons!)

Karl wrote on

Nice, I welcome the new design

Andrew wrote on

Looks great!

I use Thunderbird on KDE Neon which is Ubuntu based. A simple but annoying issue is that I can’t drag and drop an e-mail to a location to store the e-mail as .eml

I know that I can store the e-mai with a rigth click, but sometimes it is easier to drag and drop it if e.g. the location is already open with the file browser.

I think it is working for Windows but it is not working for Linux e.g. KDE neon.

Shreyas Zare wrote on

Please fix threads feature. Right now, there are emails being grouped into threads when there is absolutely nothing related to each other, i.e. no relation with content nor with senders.

Would be best to have threads that work like Gmail which just uses the subject line to group by mails into threads.


Margaret Skinner wrote on

I am 75 years old and use Thunderbird as it is so easy and simple. I am frightened with all the changes that I won’t be able to cope.
Will you publish a printable an explanation of how to use the new programming for us oldies?

Jason Evangelho wrote on

Hi Margaret, please remember that the changes we’re previewing in this blog post are all optional! That being said, we will ensure there is a guide showing veteran users how to retain their current interface and workflow. It may simply remain the default, though!

Steve wrote on

This looks good, and I am cautiously optimistic. Where I am hoping for the most improvements, though, is the calendaring, which was what pushed me over to Evolution.
It is particularly good that things like the Unified Inbox (which I personally dislike) is a configurable option. Open Source is about giving people multiple ways to do something and letting them pick the one that works for them, rather than forcing One True Way on them (cough-chrome-cough)

Jason Evangelho wrote on

Hey Steve, we’re trying to make quality improvements to Calendar as well. Check this out:

thepsychobuck wrote on

The “get messages” button looks more like a download button than a refresh button.

Gerhard Wiesinger wrote on

That user interface is NOT feasible for power users with many folders (e.g. 100) at all. Spacing is far too much. and takes too much place E.g. folder pane fits now on one screen where you have to scroll afterwards. Please don’t make a regression for all of the power users with many folders regarding user experience.

Jason Evangelho wrote on

Maybe you didn’t read the entire post? You can continue enjoying the same interface style and workflow that you’re used to.

Santanu Gon wrote on

Along with the UI it will be great and useful if Thunderbird 115 has support for an advanced Rich Text editor similar to MS Outlook and an improved font rendering. I’m not sure why it happens, when I am composing an email the font rendering (size, typeface) appears very small (tiny), but in the sent mail folder the actual size is displayed.

Support for a spell checker, like Grammarly, will be very helpful.

Susan Warren wrote on

I got my first laptop 20 years ago. I was clueless. A friend suggested Mozilla Thunderbird and I fell in love with it. I don’t like any of the other options. I find T-Bird to be the easiest to use. I freaked out last year when a big change was coming, and it turned out to be a false alarm. I am not good with any changes….because I am not computer savvy. I always have to call a friend to come help! So, knowing we can stick with the old rather than switch is very comforting. Perhaps I will slowly look into some of the changes, but I have no problem with it as it is. I cannot imagine not having T-bird. Thank you all for keeping it going…and not forcing us to learn new stuff…at my age that’s pretty miserable.

Jason Evangelho wrote on

Thank YOU for being on this journey with us!

Jorge Toledo wrote on

These updates are awesome. The care you are putting into communicating with the community is very noticeable.

Jason Evangelho wrote on

Thank you, Jorge. And sorry for approving your comment so late!

Gil wrote on

You can use the LanguageTool on the current version. I was using Grammarly in the past, but migrated into this open source software alternative; it has almost all the features as Grammarly, if you buy premium.

You can find the Thunderbird extension here:

Sam wrote on

@Jason Great stuff. I’m CEO of a startup. A TBird user of >15 years. I donated €200 at xmas. I love what you’re doing.

Matias wrote on

Just wanted to say that this looks *really* nice, and I can’t wait to try it out!
Thanks for all your hard work. Thunderbird is no doubt my favourite e-mail client, and I love how it has improved over the years.

I hope you’re proud of what you’ve made, because this is 100% pure quality!

Have a great day!

Comments are closed.