1996449 - DisplayMenuBar enterprise policy overrides user choice

Status: VERIFIED FIXED

(Firefox :: Enterprise Policies, defect)

Description

[k4sum1]

Steps to reproduce:

Make a distribution\policies.json file in Firefox install directory.
Add these contents

{
    "policies": {
        "DisplayMenuBar": true
    }
}

Start web browser
Disable menu bar
Close web browser
Start web browser

Actual results:

The menu bar shows again even though the user disabled it.

Expected results:

The menu bar should stay disabled.

Comment 1

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

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

Comment 2

[k4sum1]

I'm pretty sure this commit is the cause of the issue, but I haven't explicitly tested reverting it.
https://github.com/mozilla-firefox/firefox/commit/0aa2101448acfbcb1f040301efda15428abce5ff
https://hg-edge.mozilla.org/mozilla-central/rev/98bcb3a4ff0a

I can say this is the first build to have the issue, and this build is the first to have that commit.
https://archive.mozilla.org/pub/firefox/nightly/2025/07/2025-07-29-21-04-51-mozilla-central/

Comment 3

[k4sum1]

I don't know why sending a comment Untriaged the bug, so I added it back to Enterprise Policies

Comment 4

[k4sum1]

I discovered default-on is also valid for DisplayMenuBar, and I tested it, and thought oh they changed the behavior for true and default-on works, but no, I need to add quotes around "default-on" for it to work in the policies.json, and it also shows the issue here when set.

Comment 5

[k4sum1]

I finally got around to testing it, and yes this commit is the issue.

Comment 6

[Emilio Cobos Álvarez [:emilio]]

Attachment: Bug 1996449 - Ensure runOncePerModification("displayMenuBar", ..) works as expected. r=mkaply

runOncePerModification works on strings. If you pass a boolean down it
will always call its callback (because "true" != true etc).

Comment 7

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

Set release status flags based on info from the regressing bug 1979014

Comment 8

[k4sum1]

I sent this on Matrix, but I'll also send it here. Applying this patch fixes the issue. Thank you.

Comment 9

[Pulsebot]

Pushed by [e-mail]:
https://github.com/mozilla-firefox/firefox/commit/0df9ebba38e6
https://hg.mozilla.org/integration/autoland/rev/2c05e0d5a24d
Ensure runOncePerModification("displayMenuBar", ..) works as expected. r=mkaply,mossop

Comment 10

[Pulsebot]

Pushed by [e-mail]:
https://github.com/mozilla-firefox/firefox/commit/692919af61da
https://hg.mozilla.org/integration/autoland/rev/5c2eeca67079
Revert "Bug 1996449 - Ensure runOncePerModification("displayMenuBar", ..) works as expected. r=mkaply,mossop" for causing bc failures @browser_policy_display_menu.js.

Comment 11

[agoloman]

Backed out for causing bc failures @browser_policy_display_menu.js.

• Backout link
• Push with failures
• Failure Log

Comment 12

[Emilio Cobos Álvarez [:emilio]]

On macOS we have the native menubar so we can't hide it. I'll reland with the subtest effectively skipped there.

Comment 13

[Pulsebot]

Pushed by [e-mail]:
https://github.com/mozilla-firefox/firefox/commit/eae85737b795
https://hg.mozilla.org/integration/autoland/rev/8512344cba25
Ensure runOncePerModification("displayMenuBar", ..) works as expected. r=mkaply,mossop

Comment 14

[Sandor Molnar[:smolnar]]

https://hg.mozilla.org/mozilla-central/rev/8512344cba25

Comment 15

[Ardelean Oana, Desktop Test Engineering [:oardelean]]

Reproducible on a 2025-10-26 Firefox Nightly build on Windows 10.

Verified as fixed on Firefox Nightly 147.0a1 and Firefox 146.0b5 on Windows 10 and Ubuntu 22.