2071678 - [Nova] Sidebar border boundary has become low contrast in private windows with vertical tabs

Status: VERIFIED FIXED

(Firefox :: Private Browsing, defect)

Description

[Kestrel]

Attachment: Private window sidebar with low contrast border edges

STR:

1. Launch latest Nightly 158.0a1 with browser.nova.enabled = true.
2. Enable vertical tabs.
3. Open a private window.
4. Open the sidebar.

Expected:
Sidebar boundary has good contrast like before.

Actual:
Sidebar boundary has low contrast.

Does not occur with horizontal tabs or when window is inactive.

Regression window:
https://hg.mozilla.org/integration/autoland/pushloghtml?fromchange=9dc0d9d070a3fcd51cdd783596c655c3e273e212&tochange=3a7d6c730a3cd9770b0c1f00b14d2aa3af8865a0

Regressed by Bug 2069503.

Comment 1

[BugBot [:suhaib / :marco]]

:emilio, since you are the author of the regressor, bug 2069503, could you take a look? Also, could you set the severity field?

For more information, please visit BugBot documentation.

Comment 2

[Emilio Cobos Álvarez [:emilio]]

Attachment: Bug 2071678 - Flip active / inactive frame color in private window theme. r=sfoster!

This gets the color that Figma shows on the active window. I think
this is because Figma has some sort of rgba(0, 0, 0, .1) drop shadow
which effectively makes it a bit darker?

But not an expert on our Figma stuff so please double-check.

Comment 3

[Frederik Braun [:freddy]]

Drive-by setting Severity as the REO for Securitay/Privacy/Networking in the next 4 weeks. S3 seems to align with the fact that Nova is not yet the default, but go ahead and adjust if things change.

Comment 4

[Pulsebot]

Pushed by [e-mail]:
https://github.com/mozilla-firefox/firefox/commit/ee6af40faaaa
https://hg.mozilla.org/mozilla-central/rev/90329d0add5b
Flip active / inactive frame color in private window theme. r=sfoster,desktop-theme-reviewers

Comment 5

[Sandor Molnar[:smolnar]]

https://hg.mozilla.org/mozilla-central/rev/90329d0add5b

Comment 6

[BugBot [:suhaib / :marco]]

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

• If yes, please nominate the patch for beta approval.
  • See https://wiki.mozilla.org/Release_Management/Requesting_an_Uplift for documentation on how to request an uplift.
• If no, please set status-firefox157 to wontfix.

For more information, please visit BugBot documentation.

Comment 7

[Phabricator Automation]

firefox-beta Uplift Approval Request

• User impact if declined/Reason for urgency: comment 0
• Code covered by automated testing?: yes
• Fix verified in Nightly?: yes
• Needs manual QE testing?: yes
• Steps to reproduce for manual QE testing: comment 0
• Risk associated with taking this patch: low
• Explanation of risk level: Trivial manifest change
• String changes made/needed?: none
• Is Android affected?: yes

Comment 8

[Emilio Cobos Álvarez [:emilio]]

Attachment: Bug 2071678 - Flip active / inactive frame color in private window theme.

This gets the color that Figma shows on the active window. I think
this is because Figma has some sort of rgba(0, 0, 0, .1) drop shadow
which effectively makes it a bit darker?

But not an expert on our Figma stuff so please double-check.

Original Revision: https://phabricator.services.mozilla.com/D325685

Comment 9

[Phabricator Automation]

firefox-beta Uplift Approval Request

• User impact if declined/Reason for urgency: comment 0
• Code covered by automated testing?: yes
• Fix verified in Nightly?: yes
• Needs manual QE testing?: yes
• Steps to reproduce for manual QE testing: comment 0
• Risk associated with taking this patch: low
• Explanation of risk level: Trivial manifest change
• String changes made/needed?: none
• Is Android affected?: no

Comment 10

[Emilio Cobos Álvarez [:emilio]]

Attachment: Bug 2071678 - Flip active / inactive frame color in private window theme.

This gets the color that Figma shows on the active window. I think
this is because Figma has some sort of rgba(0, 0, 0, .1) drop shadow
which effectively makes it a bit darker?

But not an expert on our Figma stuff so please double-check.

Original Revision: https://phabricator.services.mozilla.com/D325685

Comment 11

[Simona Badau, Desktop Test Engineering]

Reproduced the initial issue of Firefox 157.0b1 (Build ID: 20260914090352) on Windows 11.

While verifying this issue on the latest Nightly 158.0a1 (Build ID: 20260915213902) I've noticed that the same low contrast of the Sidebar is now displayed when the window is inactive - please see the screen recording for more details.

@Emilio - is this the expected behavior?

Comment 12

[Emilio Cobos Álvarez [:emilio]]

Yes

Comment 13

[Simona Badau, Desktop Test Engineering]

I can confirm using the latest Nightly 158.0a1 (Build ID: 20260916094607) on Ubuntu 24.04, macOS 26 and Windows 11 that the Sidebar boundary has good contrast in the active private window when Vertical tabs are enabled.

Based on this and Comments 11 and 12, marking this as Verified fixed on firefox158.

Comment 14

[Pascal Chevrel (relman team) -> :pascalc]

Comment on attachment 9642374 [details]
Bug 2071678 - Flip active / inactive frame color in private window theme.

Duplicate request

Comment 15

[Pulsebot]

https://github.com/mozilla-firefox/firefox/commit/264c5b47da39
https://hg.mozilla.org/releases/mozilla-beta/rev/1f6854a6a996

Comment 16

[Simona Badau, Desktop Test Engineering]

Verified as fixed using Firefox 157.0b3 (treeherder build ID: 20260916171654) on macOS 26, Ubuntu 24.04 and Windows 11 - the active/inactive frame colors in the private window theme are flipped so that the Sidebar boundary has good contrast when active.