av9ash/GitBugs huggingface dataset:
Bug: Intermittent comm/mailnews/import/test/unit/test_ThunderbirdProfileImporter.js | Assertion failure: staticPrefValue == preferenceValue
Status: RESOLVED
Priority: P5
Resolution: FIXED
Created: 2023-05-28 23:16:23+00:00
Resolved: 2023-05-29 09:47:46+00:00

**Filed by:** geoff [at] darktrojan.net
**Parsed log:** https://treeherder.mozilla.org/logviewer?job_id=417331439&repo=comm-central
**Full log:** https://firefox-ci-tc.services.mozilla.com/api/queue/v1/task/EjuGQtZiROWH3UrKWDokaw/runs/0/artifacts/public/logs/live_backing.log

---
```

```
Bug: Startup Crash in [@ mozilla::widget::SessionChangeObserver::SessionChangeObserver]
Status: RESOLVED
Priority: --
Resolution: WORKSFORME
Created: 2023-05-29 02:23:58+00:00
Resolved: 2023-12-31 01:52:50+00:00

The vast majority of crashes have uptime 1 second or less.

For example bp-1934567d-a666-4f05-be05-ec1560230525.

And Crash report: https://crash-stats.mozilla.org/report/index/586ad3fc-bf41-408f-b0cf-5f4440230528

Reason: ```EXCEPTION_ACCESS_VIOLATION_READ```

Top 10 frames of crashing thread:
```
0  xul.dll  mozilla::widget::SessionChangeObserver::SessionChangeObserver  widget/windows/WinEventObserver.cpp:180
1  xul.dll  static mozilla::widget::SessionChangeObserver::Create  widget/windows/WinEventObserver.cpp:170
2  xul.dll  mozilla::widget::WinWindowOcclusionTracker::WinWindowOcclusionTracker  widget/windows/WinWindowOcclusionTracker.cpp:492
3  xul.dll  static mozilla::widget::WinWindowOcclusionTracker::Ensure  widget/windows/WinWindowOcclusionTracker.cpp:352
4  xul.dll  static gfxPlatform::InitLayersIPC  gfx/thebes/gfxPlatform.cpp:1299
5  xul.dll  static gfxPlatform::Init  gfx/thebes/gfxPlatform.cpp:963
6  xul.dll  static gfxPlatform::GetPlatform  gfx/thebes/gfxPlatform.cpp:468
7  xul.dll  mozilla::widget::GfxInfo::GetDWriteEnabled  widget/windows/GfxInfo.cpp:68
8  xul.dll  NS_InvokeByIndex  
9  xul.dll  static XPCWrappedNative::CallMethod  js/xpconnect/src/XPCWrappedNative.cpp:1125
```
Bug: Modal Dialog Origin Spoof on Thunderbird
Status: RESOLVED
Priority: --
Resolution: WORKSFORME
Created: 2023-05-29 05:03:28+00:00
Resolved: 2025-01-18 13:58:01+00:00

We are able to spoof the Origin of the Modal Dialog on Thunderbird using setTimeout().

PoC: <object data="data:text/html,<script>setTimeout(function() {prompt('Enter your password in order to continue!')},300);</script>"></object>
<script>setTimeout(function() {location="https://www.google.com"}, 0);</script>

Test on: https://pwning.click/tbdialogspoof.php
Bug: Popup menu for filter move-to destination stuck when openend
Status: NEW
Priority: --
Created: 2023-05-29 06:49:06+00:00
Resolved: 2024-11-26 11:40:35+00:00

Thunderbird 102.11.0 on Linux Ubuntu 23.04 (Linux 6.2.0-1003-lowlatency #3-Ubuntu SMP PREEMPT_DYNAMIC x86_64 GNU/Linux, )

When I create a new filter and want to select a folder where to move the messages to on match, I can browse the folder structure only in one direction, as soon as a level has been opened I cannot go back (see video), only the "esc" key brings me back one level.

Note: I do not know (and cannot check easily) if it could make a difference, but I have more than one account configured in Thunderbird.
Bug: Wrong sub menu on columns right-click
Status: RESOLVED
Priority: --
Resolution: FIXED
Created: 2023-05-29 07:45:31+00:00
Resolved: 2023-06-03 10:36:21+00:00

User Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:109.0) Gecko/20100101 Firefox/109.0

Steps to reproduce:

When right-clicking on the columns header of the messages list, it will expand a message sub menu in stead of the column settings menu.


Actual results:

Opens wrong menu


Expected results:

Open columns settings menu
Bug: Irrevocably deletes whole paragraph when undoing format change
Status: UNCONFIRMED
Priority: --
Created: 2023-05-29 09:46:47+00:00
Resolved: 2023-05-29 12:06:25+00:00

User Agent: Mozilla/5.0 (X11; Linux x86_64; rv:102.0) Gecko/20100101 Firefox/102.0

Steps to reproduce:

1. Start writing a new e-mail
2. Write a paragraph
3. Change paragraph format
4. Undo (ctrl-z)

Operating System: openSUSE Leap 15.4
KDE Plasma Version: 5.24.4
KDE Frameworks Version: 5.90.0
Qt Version: 5.15.2
Kernel Version: 5.14.21-150400.24.60-default (64-bit)
Graphics Platform: X11
Processors: 16 × AMD Ryzen 7 1700X Eight-Core Processor
Memory: 62.7 Gibyte of RAM
Graphics Processor: NVIDIA GeForce GT 1030/PCIe/SSE2


Actual results:

Thunderbird deletes the whole paragraph, with no way to get it back. Redo is grayed out. Undo is not grayed out, but does nothing.


Expected results:

The paragraph format should be changed back
Bug: Drag & dropping in the folders tree should have an overcolor (for the destination folder)
Status: RESOLVED
Priority: --
Resolution: FIXED
Created: 2023-05-29 09:50:17+00:00
Resolved: 2023-06-27 09:56:13+00:00

STR:
1. Over with mouse folders in folders tree
2. Drag with the mouse a message into another folder of the folder tree

Actuals:
1. Over color shown
2. No over color is shown while dragging a message to move it

Expected:
While dragging a message to move it an over color should be shown & be different than the one shown for simple overing
Bug: Buttons on calendar invitation bar are unreadable in Dark Mode
Status: RESOLVED
Priority: --
Resolution: DUPLICATE
Created: 2023-05-30 02:53:20+00:00
Resolved: 2023-06-01 13:50:13+00:00

Thunderbird 114.0b5
Mac OS Ventura 13.3

## Steps to reproduce:
1. Receive an email with a calendar invitation
2. open the email
3. Observe purple bar at top of email

## Actual Results

See attached screenshot

## Desired Results

I should be able to see what the buttons say on them.
Bug: Mismatch of email header to email; wrong email appears in preview and when opening email
Status: RESOLVED
Priority: --
Resolution: INCOMPLETE
Created: 2023-05-30 06:39:28+00:00
Resolved: 2023-09-29 14:25:23+00:00

User Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/113.0.0.0 Safari/537.36

Steps to reproduce:

I see an email in my inbox, from "Joe". When I select it, the preview window shows a different email, a completely different one, from "Bob". When I double-click the email header in the (gmail) inbox, it appears as the email from "Bob".

Logging in to gmail directly, I see that it is in fact the email from "Joe", and that the email from "Bob" is not located in the inbox (I had moved this email to a subfolder of the inbox, otherwise known as a gmail label).

It seems like a pretty significant error.


Actual results:

I have tried deleting the cache, to no avail. Closed and re-opened TB, to no avail.


Expected results:

When I click or double-click the email from "Joe", it should show the email from "Joe".
Bug: "Copy Email Address" does not copy anything if other text is selected in the message pane
Status: RESOLVED
Priority: --
Resolution: WORKSFORME
Created: 2023-05-30 08:43:13+00:00
Resolved: 2023-09-16 02:39:01+00:00

User Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/113.0.0.0 Safari/537.36

Steps to reproduce:

1) Open a message containing an email address
2) Select some text in the message pane (can also be a part of the contained email address)
3) Right-click the email address in the message pane and select "Copy Email address"


Actual results:

Clipboard contents does not change (i.e., contains whatever was there before clicking the "Copy Email address" context menu item)


Expected results:

Clipboard should now contain the copied email address
Bug: Replying to mail from me picks the recipients address as from address
Status: RESOLVED
Priority: --
Resolution: INCOMPLETE
Created: 2023-05-30 10:59:49+00:00
Resolved: 2023-10-07 18:20:58+00:00

Steps to reproduce:

I replied to an e-mail sent by me to a coworker. So we both have the same domain in the address.


Actual results:

Mozilla picked the recipient of the original e-mail (my coworker) as the sender of the new mail.

Mail A:
From: me@example.com
To: coworker@example.com

Mail B, me replying to Mail A:
From: coworker@example.com
To: coworker@example.com

There is the possibility to click the dropdown for the From field when writing Mail B and choosing the correct sender. But it is easily missed.

This only happens when I'm the sender of the original email (Mail A). And both addresses have my account domain. And "Reply with this identity when delivery headers match:" is checked in account settings. The value of the field is "*@example.com".

(@example.com just used as an example, not my real domain).


Expected results:

Mozilla should always by default keep me as the sender of the e-mail. Especially if "Reply with this identity when delivery headers match" is checked.

It works correctly if the mentioned setting is unchecked. Which is a bit counterintuitive.
Bug: Failure to automatically display protected header subject for plain text only messages
Status: UNCONFIRMED
Priority: --
Created: 2023-05-30 11:46:17+00:00
Resolved: 2023-05-30 13:44:39+00:00

Steps to reproduce:

Thunderbird fails to automatically display the subject when using protected headers for plain text only messages.

This is present on at least v102.4, v102.11.1, v102.11.2 and most likely all other versions.

Steps to reproduce:

Using the example from https://datatracker.ietf.org/doc/id/draft-autocrypt-lamps-protected-headers-02.html#name-signed-and-encrypted-pgp-mi

1. Copy the following content and then encrypt it with your own public key that you  have available in Thunderbird. (E.g `gpg --encrypt -r me@example.com -a msg.txt`)

From: Alice Lovelace <alice@openpgp.example>
To: Bob Babbage <bob@openpgp.example>
Date: Mon, 21 Oct 2019 07:09:00 -0700
Subject: BarCorp contract signed, let's go!
Content-Type: text/plain; charset="us-ascii"; protected-headers="v1"
Message-ID: <pgpmime-sign+enc@protected-headers.example>

Hi Bob!

This is a plain text only message.

Thanks, Alice

2. Paste your encrypted content in this email and save it:

Received: from localhost (localhost [127.0.0.1]); Mon, 21 Oct 2019
 07:09:28 -0700 (UTC-07:00)
MIME-Version: 1.0
Content-Type: multipart/encrypted; boundary="ca4";
 protocol="application/pgp-encrypted"
From: Alice Lovelace <alice@openpgp.example>
To: Bob Babbage <bob@openpgp.example>
Date: Mon, 21 Oct 2019 07:09:00 -0700
Message-ID: <pgpmime-sign+enc@protected-headers.example>
Subject: ...

--ca4
content-type: application/pgp-encrypted

Version: 1

--ca4
content-type: application/octet-stream

-----BEGIN PGP MESSAGE-----

...your encrypted message...
-----END PGP MESSAGE-----

--ca4--

3. Open the above saved email in Thunderbird and you will see that the subject shown is "..." instead of the encrypted "BarCorp contract signed, let's go!".

I've tried using other mail clients such as Fair Email and K-9 mail, both of which are able to correctly display the protected header subject line.

The strange thing is that if you add the following "--" on its own line anywhere to the plain text message then Thunderbird is able to display the correct subject.

So I'm not sure if the bug is related to boundaries or something.

For example the following plain text content will work and Thunderbird will correctly display the real subject:

From: Alice Lovelace <alice@openpgp.example>
To: Bob Babbage <bob@openpgp.example>
Date: Mon, 21 Oct 2019 07:09:00 -0700
Subject: BarCorp contract signed, let's go!
Content-Type: text/plain; charset="us-ascii"; protected-headers="v1"
Message-ID: <pgpmime-sign+enc@protected-headers.example>

Hi Bob!

This is a plain text only message.

Thanks, Alice
--


Actual results:

Thunderbird does not automatically display the encrypted subject from the protected headers just the "..." subject is displayed.


Expected results:

Thunderbird should automatically display the subject from the protected headers like it does with HTML / mixed emails.
Bug: Emails Scrambled. i.e. Sender/message are mixed up in the message pane
Status: RESOLVED
Priority: --
Resolution: INCOMPLETE
Created: 2023-05-30 17:00:01+00:00
Resolved: 2023-07-15 05:09:09+00:00

User Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:109.0) Gecko/20100101 Firefox/113.0

Steps to reproduce:

I'm now using the new 115 Supernova version which isn't a choice above. 

I read an email. When I went to read it again the sender and message were changed from first time.  This happened a few times with the previous version of Thunderbird.


Actual results:

You can see from the screenshot attached the subject line was Prayer Chain Update, (from my church) but the message showing is actually from The Lerner Theater.


Expected results:

It should have displayed a message about a friend who needs prayer.  I can no longer find that message.
Bug: Toolbar and Menubar text color are dark text on dark background in Dark theme on Linux
Status: RESOLVED
Priority: --
Resolution: FIXED
Created: 2023-05-30 18:07:25+00:00
Resolved: 2023-05-31 17:11:09+00:00

The text on the old toolbars and menubars are black text on a dark grey background on linux when using a dark theme.
Bug: open message from advanced search messages doesn't work
Status: RESOLVED
Priority: --
Resolution: WORKSFORME
Created: 2023-05-31 05:05:09+00:00
Resolved: 2023-05-31 07:25:07+00:00

Opening message from advanced search messages doesn't work.

Uncaught TypeError: contentWindow.displayMessage is not a function
    displayMessage chrome://messenger/content/messageWindow.js:209
    openMessageInExistingWindow resource:///modules/MailUtils.jsm:266
    displayMessages resource:///modules/MailUtils.jsm:206
    MsgOpenSelectedMessages chrome://messenger/content/SearchDialog.js:646
    ThreadPaneDoubleClick chrome://messenger/content/threadPane.js:464
    ThreadPaneOnClick chrome://messenger/content/threadPane.js:307
2 messageWindow.js:209:17
Bug: When switching from one Unified folder (e.g. Inbox) to another Unified folder (e.g. Sent), the Threads Pane (message list) goes blank for 15 seconds.
Status: RESOLVED
Priority: --
Resolution: WORKSFORME
Created: 2023-05-31 16:17:16+00:00
Resolved: 2024-08-08 19:17:51+00:00

User Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:109.0) Gecko/20100101 Firefox/113.0

Steps to reproduce:

Using Beta 114.0b5 (64-bit) I have two email accounts using the unified inbox.


Actual results:

 Using the Unified Inbox I find that the message list is blank for at least 15 seconds when first loading. 


Expected results:

It should populate immediately, as it does in the stable version
Bug: [ Thunderbird Wayland port ] close sub-window crashes whole application
Status: RESOLVED
Priority: --
Resolution: INCOMPLETE
Created: 2023-05-31 16:40:49+00:00
Resolved: 2024-03-02 17:03:25+00:00

User Agent: Mozilla/5.0 (X11; Linux x86_64; rv:109.0) Gecko/20100101 Firefox/113.0

Steps to reproduce:

Environment:
[IP-] [  ] sys-kernel/gentoo-sources-6.3.5:6.3.5
[IP-] [  ] x11-drivers/nvidia-drivers-535.43.02:0/535
[IP-] [  ] dev-libs/wayland-9999:0
[IP-] [  ] dev-libs/wayland-protocols-9999:0
[IP-] [  ] gui-libs/egl-wayland-1.1.11_p20230202-r1:0
[IP-] [  ] x11-base/xwayland-9999:0
[I-O] [  ] gui-apps/wlr-randr-9999:0
[IP-] [  ] gui-libs/wlroots-9999:0/9999
[I-O] [  ] gui-wm/dwl-9999-r1:0

Version:
[IP-] [  ] mail-client/thunderbird-102.11.2:0

A)
o) Start Thunderbird Application --> Main window
o) Stop Thunderbird Application --> Multiple warnings

B.1)
o) Start Thunderbird Application --> Main window
o) Create new message  ("Verfassen")
o) Close this sub-window via ^W
o) The whole Tb app crashes.

B.2)
o) Start Thunderbird Application --> Main window
o) Re-use existing message  ("Als neu bearbeiten")
o) Close this sub-window via ^W
o) The whole Tb app crashes.



Actual results:

All warnings / crashes seem to be related around
[...]  -> zwp_linux_dmabuf_v1 . . .
[...]  -> zwp_linux_dmabuf_feedback_v1 . . .
in the end.

Traces retrieved by starting via "WAYLAND_DEBUG=1   thunderbird"
are provided in the attachment.


Expected results:

Don't crash, but close politely ;-)

This bug may block
--> Bug 1542587 (tbwayland)
--> [meta] Thunderbird Wayland port
Bug: Clicking spam flag of non-spam message in spam folder on moves from Junk folder to Inbox
Status: RESOLVED
Priority: --
Resolution: FIXED
Created: 2023-05-31 17:20:19+00:00
Resolved: 2023-06-12 11:48:43+00:00

With Thunderbird Daily (build 20230531081622) adding the spam flag to a message in the Junk folder by clicking the toggle button in the Spam column of the message list causes the message to be moved from the Junk folder to the Inbox.  To reproduce:

1. Copy a message (e.g. one in Drafts or Inbox) to the Junk folder.  Note that although the message is in the Junk folder, it is not flagged as spam in the message list.
2. Click on the flame in the Spam column of the message list to flag the message as spam.
3. Observe that instead of flagging the message as spam, the message is moved to the Inbox (and remains not flagged as spam).

I've bisected the regression to pushlog https://hg.mozilla.org/comm-central/pushloghtml?fromchange=ac9a362c58ff13eb34a60516a9eea242527cc232&tochange=c4742f6c06abe8c25545f3e2f21bf2da8820ca13 which suggests this was regressed by Bug 1824555.
Bug: Double click and drag on a palette item makes it disappear
Status: ASSIGNED
Priority: --
Created: 2023-05-31 17:55:45+00:00
Resolved: 2023-12-14 10:15:13+00:00

STR
- Open unified toolbar customization view
- Quickly double click (repeatedly) on a palette item and drag it at the same time

The buttons suddenly disappear.
Bug: :) smiley renders as wrong emoji
Status: RESOLVED
Priority: --
Resolution: DUPLICATE
Created: 2023-05-31 19:26:54+00:00
Resolved: 2023-06-05 11:48:35+00:00

User Agent: Mozilla/5.0 (X11; Linux x86_64; rv:109.0) Gecko/20100101 Firefox/113.0

Steps to reproduce:

Typed :)


Actual results:

The :) smiley gets rendered as 😄. This is wrong.


Expected results:

It should render as 🙂.
Bug: create an event is missing in Beta 114.0b5 (64-bit)
Status: RESOLVED
Priority: --
Resolution: DUPLICATE
Created: 2023-05-31 20:18:32+00:00
Resolved: 2023-06-09 06:05:33+00:00

User Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:109.0) Gecko/20100101 Firefox/113.0

Steps to reproduce:

I wanted to create an event from an email


Actual results:

The drop-down option for create an event is missing in Beta 114.0b5 (64-bit)
Bug: Slow population of message header
Status: RESOLVED
Priority: --
Resolution: DUPLICATE
Created: 2023-06-01 00:27:48+00:00
Resolved: 2024-05-20 03:14:27+00:00

User Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/113.0.0.0 Safari/537.36

Steps to reproduce:

I have 13 e-mail accounts. I go through each inbox and handle each e-mail.


Actual results:

Displaying e-mail control section above the preview pane is very slow at times.
- The subject from the previous e-mail persists for up to 10 seconds at times.
- The buttons also do not display for quite a few seconds (10-15).


Expected results:

Old TB version always had a display that was fast and had subject of the currently displayed e-mail.
Bug: UnknownCollectionError: Unknown Collection "thunderbird/translations-models"
Status: NEW
Priority: --
Created: 2023-06-01 01:23:50+00:00
Resolved: 2023-10-04 19:10:51+00:00

+++ This bug was initially created as a clone of Bug #1830216 +++

I've started getting this spew showing up in the console for my builds:

UnknownCollectionError: Unknown Collection "thunderbird/translations-models"
    UnknownCollectionError resource://services-settings/RemoteSettingsClient.sys.mjs:192
    sync resource://services-settings/RemoteSettingsClient.sys.mjs:616
RemoteSettingsClient.sys.mjs:532:15
    get resource://services-settings/RemoteSettingsClient.sys.mjs:532
Translations: Error: Unable to retrieve the translation models.
    #getTranslationModelRecords resource://gre/actors/TranslationsParent.sys.mjs:887
TranslationsChild.sys.mjs:520:66
    handleEvent resource://gre/actors/TranslationsChild.sys.mjs:520
Bug: Message shown twice in Unified Folders
Status: RESOLVED
Priority: --
Resolution: FIXED
Created: 2023-06-01 07:38:44+00:00
Resolved: 2024-05-06 16:45:15+00:00

User Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:109.0) Gecko/20100101 Firefox/113.0

Steps to reproduce:

Use grouped folders and wait for mails to be received


Actual results:

Sometimes, mails are shown twice (as if they were two mails). 
When switching to All Folders, you see that there is only one mail.

Same behaviour in TB 114


Expected results:

No phantom duplicate of the mail
Bug: Unable to configure CardDAV because new CardDAV Address book dialog doesn't resize after fetching available address books
Status: RESOLVED
Priority: --
Resolution: FIXED
Created: 2023-06-01 07:46:22+00:00
Resolved: 2023-07-27 14:20:11+00:00

+++ This bug was initially created as a clone of Bug #1744144 +++

**STR**

- New Address Book tab
- Select `Add CardDav Address Book`
- Fill up the fields and click continue

If multiple address books are available and listed, the dialog doesn't resize properly to accommodate the new content, resulting in the buttons being pushed outside the viewport area.
Bug: Intermittent comm/mail/components/extensions/test/browser/browser_ext_browserAction_customized.js | Light theme should use dark icon.
Status: RESOLVED
Priority: P5
Resolution: FIXED
Created: 2023-06-01 08:12:45+00:00
Resolved: 2024-01-17 12:10:01+00:00

**Filed by:** geoff [at] darktrojan.net
**Parsed log:** https://treeherder.mozilla.org/logviewer?job_id=417743543&repo=comm-central
**Full log:** https://firefox-ci-tc.services.mozilla.com/api/queue/v1/task/ROUV2T6PTderviQnI_HvWQ/runs/0/artifacts/public/logs/live_backing.log

---
```

```
Bug: Disable unified toolbar customization until spaces toolbar is initialized
Status: RESOLVED
Priority: --
Resolution: FIXED
Created: 2023-06-01 08:13:41+00:00
Resolved: 2023-06-12 11:48:45+00:00

Currently the unified toolbar customization is immediately available. It should only be available once the spaces toolbar is initialized. Optimally we'd handle this not only with a hard check before initializing the customization but also by disabling relevant menu items until the customization is usable.
Bug: Thunderbird "view / message body as / plain text" should show plain text part
Status: RESOLVED
Priority: --
Resolution: INVALID
Created: 2023-06-01 13:21:29+00:00
Resolved: 2023-06-01 14:52:42+00:00

I've verbally received the following bug report, which I haven't yet verified:

If the TB mail display window is configured as "view / message body as / plain text", and a received email contains alternative HTML and plain text message parts, then:

actual behavior:
TB shows the result of the HTML message part to plain text

expected behavior:
TB should show the received plain text part, and ignore the HTML part
Bug: mail.operate_on_msgs_in_collapsed_threads at false resulting in: Can't collapse thread if row is selected
Status: RESOLVED
Priority: --
Resolution: DUPLICATE
Created: 2023-06-01 20:25:04+00:00
Resolved: 2023-06-01 22:45:46+00:00

+++ This bug was initially created as a clone of Bug #1820700 +++

In version 102, selecting a row that represents a thread and expanding a thread/collapsing a thread are independent.

In version 115, selecting a row now expands the thread and clicking onto the thread arrow has no effect, the thread can't be collapsed again. You can now only collapse threads with are not selected.

Note that there seems to be some confusion in bug 1820700 comment #14.
Bug: Unified folders mode randomly shows and doesn't show chevrons for smart folder
Status: RESOLVED
Priority: P2
Resolution: FIXED
Created: 2023-06-01 22:53:30+00:00
Resolved: 2023-06-13 18:54:47+00:00

STR:
- Start in All folder modes
- Activate Unified folder modes

See how the special folders all have the chevron even if you only have 1 account.

- Restart Thunderbird

The special folders don't have the chevron.

Not severe but kinda annoying, and slightly related to bug 1832698 as the list is not populated on first select when the chevrons are visible.