2027166 - Disabling split-view causes alt-clicking on a tab to do nothing

Status: RESOLVED FIXED

(Firefox :: Tabbed Browser: Split View, defect, P2)

Description

[Eetu Perälä]

User Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:150.0) Gecko/20100101 Firefox/150.0

Steps to reproduce:

In FF 150.0b2 or 151.0a1 (build 20260327092354), in about:config, set browser.tabs.splitView.enabled to false. Reproducible with a new profile.

Actual results:

Clicking on a tab while holding left alt no longer opens that tab.

Expected results:

Clicking on a tab while holding left alt should open the tab like in previous versions of Firefox.

Comment 1

[BugBot [:suhaib / :marco]]

The Bugbug bot thinks this bug should belong to the 'Firefox::Tabbed Browser' component, and is moving the bug to that component. Please correct in case you think the bot is wrong.

Comment 2

[Jonathan Sudiaman [:jsudiaman]]

mozregression output

---

2026-04-10T15:22:38.590000: DEBUG : Found commit message:
Bug 2012799 - Add ability to Alt/Opt + click a tab with a different selected tab to create a split view r=tabbrowser-reviewers,sclements

Differential Revision: https://phabricator.services.mozilla.com/D286986

2026-04-10T15:22:38.591000: DEBUG : Did not find a branch, checking all integration branches
2026-04-10T15:22:38.591000: INFO : The bisection is done.
2026-04-10T15:22:38.592000: INFO : Stopped

Comment 3

[BugBot [:suhaib / :marco]]

:kcochrane, since you are the author of the regressor, bug 2012799, could you take a look?

For more information, please visit BugBot documentation.

Comment 4

[BugBot [:suhaib / :marco]]

Set release status flags based on info from the regressing bug 2012799

Comment 5

[Kelly Cochrane [:kcochrane]]

Attachment: Bug 2027166 - Allow alt-clicking to select a tab if browser.tabs.splitView.enabled is false

Comment 6

[Pulsebot]

Pushed by [e-mail]:
https://github.com/mozilla-firefox/firefox/commit/9a893b0a8355
https://hg.mozilla.org/integration/autoland/rev/2bec96f934a7
Allow alt-clicking to select a tab if browser.tabs.splitView.enabled is false r=tabbrowser-reviewers,jsudiaman

Comment 7

[Silaghi Andreea]

https://hg.mozilla.org/mozilla-central/rev/2bec96f934a7

Comment 8

[BugBot [:suhaib / :marco]]

The patch landed in nightly and beta is affected.
:kcochrane, 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-firefox150 to wontfix.

For more information, please visit BugBot documentation.