2019753 - The about:translations page does not correctly hide the Translations URL-bar button when switching from another tab

Status: VERIFIED FIXED

(Firefox :: Translations, defect, P2)

Description

[Erik Nordin [:nordzilla]]

Description

The TranslationsParent actor is not valid for the about:translations page, and we do not allow Full-Page Translations on our internal aobut:* pages.

Bug 1970962 seems to have regressed the behavior of hiding the Full-Page Translations button from the URL bar, when switching from a translatable tab to the about:translations page.

This is strange, because the behavior works correctly for other about:* pages, such as about:settings.

---

Steps to Reproduce

1. Open the about:translations page.

2. Open a new tab, and navigate to a translatable page, e.g. https://es.wikipedia.org/wiki/Mozilla_Firefox

3. Observe that the Translations button appears in the URL bar.

4. Switch back to the about:translations tab.

Expected Behavior

The Translations button disappears from the URL bar on the about:translations page.

Actual Behavior

The Translations button remains in the URL bar on the about:translations page.

Comment 1

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

Set release status flags based on info from the regressing bug 1970962

Comment 2

[Erik Nordin [:nordzilla]]

Attachment: Bug 2019753 - Fix Translations URL-Bar Button Hiding r=sfoster!

Comment 3

[Pulsebot]

Pushed by [e-mail]:
https://github.com/mozilla-firefox/firefox/commit/2c98d2756670
https://hg.mozilla.org/integration/autoland/rev/427d5707e7b3
Fix Translations URL-Bar Button Hiding r=sfoster

Comment 4

[Sandor Molnar[:smolnar]]

https://hg.mozilla.org/mozilla-central/rev/427d5707e7b3

Comment 5

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

The patch landed in nightly and beta is affected.
:nordzilla, 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-firefox149 to wontfix.

For more information, please visit BugBot documentation.

Comment 6

[Erik Nordin [:nordzilla]]

While Bug 1970962 technically regressed this behavior for the about:translations page, which used to have custom logic to hide the Translations URL-bar button, this behavior has existed for unprivileged content about:* pages, such as about:about, for a long time. I tested as far back as January 1, 2025 with mozregression.

This has likely been an issue since the beginning of the Translations feature, just one that is very unlikely to occur due to the infrequency of visits to those kinds of internal pages only after visiting a translatable page in the same Firefox window where the button shows.

I don't think we need to uplift this.

Comment 7

[Ciprian Georgiu, Desktop QA]

Reproduced this issue with an affected Nightly build (2026-02-26) on Win 11.

The issue is verified as fixed on Beta 150.0b1 under Win 11, macOS 26 and Ubuntu 24.