1970015 - Vertical tab bar disappears when sidebar tool button is removed from toolbar. And Horizontal tabs are also not shown. i.e., tabs are completely gone

Status: VERIFIED FIXED

(Firefox :: Sidebar, defect, P2)

Description

[Alice0775 White]

Steps to reproduce:

1. Enable Vertical tabs
2. Enter Customize Toolbar...
3. Add the Sidebar tool button to the navbar
4. Exit Customize Toolbar...
5. Right mouse click on the Sidebars toolbutton and choose Remove from Toolbar

Actual Results:
The vertical Tabs disappear.
And Horizontal tabs are also not shown.

Expected Results:
The vertical tabs should remain visible.

Comment 1

[Kelly Cochrane [:kcochrane]]

The launcher will be hidden if the sidebar toolbar button is removed as of bug 1933592. We should either prevent that from happening if vertical tabs are enabled OR show horizontal tabs again if we do hide the launcher. Really a UX question.

Comment 2

[Kelly Cochrane [:kcochrane]]

Gonna switch this to P2 since it's been happening since Dec 2024 with no user complaints

Comment 3

[BugBot [:suhaib / :marco/ :calixte]]

Set release status flags based on info from the regressing bug 1933592

:nsharpley, since you are the author of the regressor, bug 1933592, could you take a look?

For more information, please visit BugBot documentation.

Comment 4

[Sarah Clements [:sclements]]

I'm confused by these STR - Alice, can you clarify how you are enabling vertical tabs first? Is that via about:preferences? But the sidebar toolbar button doesn't move, so you move it out of the Customize toolbar menu and then remove it?

Comment 5

[Alice0775 White]

(In reply to Sarah Clements [:sclements] from comment #4)

I'm confused by these STR - Alice, can you clarify how you are enabling vertical tabs first? Is that via about:preferences? But the sidebar toolbar button doesn't move, so you move it out of the Customize toolbar menu and then remove it?

1. start with new profile
2. about:preferences > check Vertical tabs
3. Right mouse click on Collapse sidebar toolbutton at the top-left. And choose Remove from Toolbar

Comment 6

[Jonathan Sudiaman [:jsudiaman]]

Currently, removing the sidebar toolbar button will completely remove sidebar functionality. Sidebar is designed to work in tandem with this button. Therefore, in this case, we should be reverting to horizontal tabs (because we have nowhere to show Vertical Tabs).

Comment 7

[Donal Meehan [:dmeehan]]

This is the final week of beta for Fx140
:jsudiaman, do you plan on landing a patch this week that might be safe for an uplift?

Comment 8

[Jonathan Sudiaman [:jsudiaman]]

Attachment: Bug 1970015 - Force horizontal tabs when sidebar button is removed. r?#sidebar-reviewers

Comment 9

[Sarah Clements [:sclements]]

(In reply to Donal Meehan [:dmeehan] from comment #7)

This is the final week of beta for Fx140
:jsudiaman, do you plan on landing a patch this week that might be safe for an uplift?

I don't see a need to uplift this so late into 140 beta.

Comment 10

[Pulsebot]

Pushed by [e-mail]:
https://github.com/mozilla-firefox/firefox/commit/8347596d0774
https://hg.mozilla.org/integration/autoland/rev/f4284b0494fc
Force horizontal tabs when sidebar button is removed. r=sidebar-reviewers,nsharpley

Comment 11

[agoloman]

https://hg.mozilla.org/mozilla-central/rev/f4284b0494fc

Comment 12

[BugBot [:suhaib / :marco/ :calixte]]

Set release status flags based on info from the regressing bug 1933592

Comment 13

[Dana Lucaci, Desktop QA]

Reproduced with Firefox 141.0a1 (2025-06-02) on macOS 15.
Verified as fixed with Firefox 142.0a1 (20250624211752) and Firefox 141.0b1 (20250624005653) on macOS 15, Windows 10 and Ubuntu 22.