1945927 - Resizing the sidebar is broken after toggling sidebar on and off

Status: VERIFIED FIXED

(Firefox :: Sidebar, defect, P1)

Description

[Stuart Colville [:muffinresearch]]

STR:

• With a new profile enable sidebar and vertical tabs (from either Fx Labs or about:preferences).
• Expand the sidebar with the sidebar button (note you can resize the vertical tabs area)
• Turn off sidebar (which disables vertical tabs)
• Reenable the sidebar and vertical tabs and expand the vertical tabs

What happens:

The resizing of the sidebar now snaps to the original position it was in and you can't resize the sidebar.

What should happen:

Resizing the vertical tabs area should still function

From running mozregression this appears to have been regressed by bug 1930199

Comment 1

[Stuart Colville [:muffinresearch]]

Attachment: Screencast showing resize snapping back to original position

Note: the screencast also shows another bug (hiding first before expanding, that's covered elsewhere so can be ignored for the purposes of this bug).

Comment 2

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

Set release status flags based on info from the regressing bug 1930199

:jsudiaman, since you are the author of the regressor, bug 1930199, could you take a look? Also, could you set the severity field?

For more information, please visit BugBot documentation.

Comment 3

[Jonathan Sudiaman [:jsudiaman]]

Attachment: Bug 1945927 - Ensure that resize observer is restored when reinitializing revamped sidebar. r?#sidebar-reviewers

Comment 4

[Pulsebot]

Pushed by [e-mail]:
https://hg.mozilla.org/integration/autoland/rev/cef2da85ff94
Ensure that resize observer is restored when reinitializing revamped sidebar. r=sidebar-reviewers,kcochrane

Comment 5

[amarc]

Backed out for causing bc failures @ browser_glean_sidebar.js

• Backout link
• Push with failures
• Failure Log
• Failure line:

TEST-UNEXPECTED-FAIL | browser/components/sidebar/tests/browser/browser_glean_sidebar.js | Two events were reported. - 3 == 2 -

Comment 6

[Pulsebot]

Pushed by [e-mail]:
https://hg.mozilla.org/integration/autoland/rev/ff0ae341ed38
Ensure that resize observer is restored when reinitializing revamped sidebar. r=sidebar-reviewers,kcochrane

Comment 7

[agoloman]

Backed out for causing bc failures @browser_customize_sidebar.js

• Backout link
• Push with failures
• Failure Log

Comment 8

[Pulsebot]

Pushed by [e-mail]:
https://hg.mozilla.org/integration/autoland/rev/b71374a4ec8d
Ensure that resize observer is restored when reinitializing revamped sidebar. r=sidebar-reviewers,kcochrane

Comment 9

[amarc]

Backed out for causing bc failures @ browser_sidebar_max_width.js

• Backout link
• Push with failures
• Failure Log
• Failure Log 2
• Failure Log 3
• Failure Log 4

Comment 10

[Pulsebot]

Pushed by [e-mail]:
https://hg.mozilla.org/integration/autoland/rev/1c9d4620d235
Ensure that resize observer is restored when reinitializing revamped sidebar. r=sidebar-reviewers,kcochrane

Comment 11

[Sandor Molnar[:smolnar]]

https://hg.mozilla.org/mozilla-central/rev/1c9d4620d235

Comment 12

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

The patch landed in nightly and beta is affected.
:jsudiaman, is this bug important enough to require an uplift?

• If yes, please nominate the patch for beta approval.
• If no, please set status-firefox136 to wontfix.

For more information, please visit BugBot documentation.

Comment 13

[Jonathan Sudiaman [:jsudiaman]]

Attachment: Bug 1945927 - Ensure that resize observer is restored when reinitializing revamped sidebar. r?#sidebar-reviewers

Original Revision: https://phabricator.services.mozilla.com/D236933

Comment 14

[Phabricator Automation]

beta Uplift Approval Request

• User impact if declined: Sidebar could possibly get into a state where it cannot be resized.
• Code covered by automated testing: no
• Fix verified in Nightly: no
• Needs manual QE test: yes
• Steps to reproduce for manual QE testing: https://bugzilla.mozilla.org/show_bug.cgi?id=1945927#c0
• Risk associated with taking this patch: Low
• Explanation of risk level: Three lines change introducing safeguards, affecting only sidebar.
• String changes made/needed: None
• Is Android affected?: no

Comment 15

[Pulsebot]

https://hg.mozilla.org/releases/mozilla-beta/rev/f7f0415b0a75

Comment 16

[Ryan VanderMeulen (PTO, back July 27)]

I don't think this needs backport to a 135 dot release if vertical tabs are needed to reproduce. Feel free to nominate if you feel strongly otherwise, however.

Comment 17

[Bianca Hidecuti, Desktop Test Engineering [:bhidecuti]]

I was able to reproduce the issue on an affected Firefox Nightly 137.0a1 build from 2025-02-04, using Windows 11, while following the steps described in Comment 0.
Verified as fixed using Firefox 136.0b6 (treeherder build from Comment 15) and Firefox Nightly 137.0a1 (2025-02-13), using Windows 11, macOS 14.7 and Ubuntu 22.04. The sidebar can be resized after toggling it on and off with vertical tabs enabled.