1993380 - Settings for spell checking are unclear

Status: ASSIGNED

(Firefox :: Settings UI, defect)

Description

[наб]

Steps to reproduce:

Type into an input box. For the purposes of this report let's say I opened <data:text/html,<textarea>asd harbor harbour> and clicked on the textarea

Actual results:

"asd" and "harbour" are red-squiggled

Expected results:

"asd" and "harbor" are red-squiggled.

In about:preferences, Language, I have selected en-gb, then en, then en-us. Thus, I expect the dictionary match this as well.

Happens on current Nightly (145.0a1 (2025-10-08) (64-bit)) on Win32.

Does not happen on DevEd 87.0b9 (64-bit) on the same machine with the same preferences (or on Debian 128.10.1esr (64-bit) with just en-gb > en).

All browsers run in environments equivalent to LANG=en-GB.UTF-8 (i.e. this is my system locale on Win32).

Toggling "Use your operating system settings for “English (GB)” to format dates, times, numbers, and measurements." doesn't do anything either I think.

Comment 1

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

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

Comment 2

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

The severity field is not set for this bug.
:m_kato, could you have a look please?

For more information, please visit BugBot documentation.

Comment 3

[Masayuki Nakano [:masayuki] (he/him)(JST, +0900)]

Sounds like a regression, could you find a regression point with mozregression? I think spellchecker code is completely cross-platform, so, you don't need to test this in multiple platforms.

Comment 4

[наб]

I tried, and with a test procedure of [run version] -> about:preferences -> [Choose your preferred language for displaying pages: remove en-us, add en-gb at the top] -> [Check "Use your operating system settings for “English (United Kingdom)” to format dates, times, numbers, and measurements."] -> open <data:text/html,<textarea>asd harbor harbour> (or <data:text/html,<textarea lang=en-GB>asd harbor harbour>) -> click on the textbox, all versions I tested fail (asd and harbour squiggled). This includes whatever mozregression picked between release:87 and date:2025-11-03, as well as version 86 and version 5. So idk what makes my regular 87 profile behave correctly I think. Am I holding it wrong?

Comment 5

[Masayuki Nakano [:masayuki] (he/him)(JST, +0900)]

Thanks. I have no idea why you couldn't find a build which worked before. I guess you forgot that you changed the setting at that time.

Comment 6

[Masayuki Nakano [:masayuki] (he/him)(JST, +0900)]

Oh, wait, in my understanding, the preferred language setting in about:preferences is for the HTTP header to let the server know the preferred languages and it's not referred by the spellchecker. The dictionary is selected by a separated pref, spellchecker.dictionary and it's referred by the spellchecker. You can add/select current dictionary from the context menu in <input> or <textarea> ("Languages" below "Check spelling" in en-US UI). Could you check the behavior with setting it?

Comment 7

[наб]

omg that's so confusing... 😭😭😭 yeah, RMB -> Languages -> Add Dictionaries... -> installing one of the addons from AMO worked

I can confidently say I don't think I've ever knowingly right-clicked on a text field. I hope you'll agree that the layout of the Preferences is really confusing (seeing as you got fooled by it too). The dictionary list could also just as well be under the checkbox in about:preferences I think.

Comment 8

[наб]

Attachment: Bug 1993380 - Document how to configure spell-check in about:preferences. r=#fluent-reviewers,#settings-reviewers

Comment 9

[наб]

The dictionary list yes (in a way so hacky it'd never pass review), any of the useful preferences no. Maybe just document how to configure this.

Comment 10

[Francesco Lodolo [:flod]]

It's not possible to configure dictionaries through the context menu if there are no dictionaries installed, so just adding text to the existing setting is not a solution.

Comment 11

[Masayuki Nakano [:masayuki] (he/him)(JST, +0900)]

How about to add a UI into about:preferences near the language setting? Then, users see the separated preference visually.

Comment 12

[наб]

Attachment: Bug 1993380 - Remove dead open-coded bits of formatURLPref() from nsContextMenu.addDictionaries(). r=mconley

uri = Services.urlFormatter.formatURLPref() which already processes
%EVERYTHING%, so both .replace()s are guaranteed no-ops

Comment 13

[Francesco Lodolo [:flod]]

As mentioned in the diff, this requires input from UX/Content. Moving to Settings for now.

Comment 14

[Mike Conley (:mconley) (:⚙️)]

Attachment: Screenshot 2025-11-10 at 18.53.11.png

Hi наб,

First off, thank you for filing this and going through the effort to supply patches.

So you find us at an interesting time in about:preferences - as you may have heard, we're in the midst of a fairly serious redesign of about:preferences. One of the things that should improve with that redesign is the spellchecking options. The screenshot I've attached shows what we have in mind.

The redesign, however, is in its early phases - the current phase that we're in is a complete refactor of about:preferences to use our reusable components, instead of the bespoke JS / XHTML / XUL mess that exists today. That phase is just starting to cook.

The metabug that this work is happening in is bug 1968037. If you see any bugs or patches related to "config-based settings", that's what we're referring to.

If you'd like to help us out with that refactor, there's a metabug specifically related to Language settings, which include spellchecking: bug 1968117.

What we'd like to avoid doing is making any non-critical changes to the old preferences mechanism, nor put any additional undue load on our content designers and localizers while we work on this transition. So for now, we thank you for your patches, but we think it'd be best to focus our energies on getting this refactor and redesign out the door as soon as we possibly can (and if you're willing and able to help, amazing!), rather than add this intermediary solution.

Comment 15

[Mark Kennedy [:mark]]

Thank you for that wonderful description, Mike!
наб we appreciate your patches and we hope Mike's description above will better explain our rationale going forward.

We added Jules during triage to get their opinion on how to proceed. But since Mike has already made the path forward clear, I'm going to remove them from needinfo.