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Maniphest T433213

Firefox renders its own text selection background on top of CodeMirror's
Closed, ResolvedPublicBUG REPORT
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Description

Steps to replicate the issue:

  • Start editing a page with Firefox
  • Turn "Syntax" on
  • Select some or all of the source

What happens?:
The selected text has the browser's native blue background on top of CodeMirror's purple background.

1.png (597×177 px, 7 KB)

What should have happened instead?:
It only has the purple background.

Other information:
Reproducible with Firefox 153 but not with Chromium 150.

Details

Related Changes in Gerrit:
SubjectAuthorRepoBranchLines +/-
codemirror.less: workaround for transparent selection style in FFMusikAnimalmediawiki/extensions/CodeMirrormaster+7 -0
Customize query in gerrit

Event Timeline

Nardog created this task.Sun, Jul 26, 10:29 PM
Restricted Application added a subscriber: Aklapper. · View Herald TranscriptSun, Jul 26, 10:29 PM
Hakimi97 subscribed.Mon, Jul 27, 12:20 AM
MusikAnimal triaged this task as Medium priority.Mon, Jul 27, 4:43 PM
MusikAnimal moved this task from Backlog to Bugs on the MediaWiki-extensions-CodeMirror board.
MusikAnimal added a project: Upstream.Mon, Jul 27, 5:05 PM
MusikAnimal subscribed.

Reproducible in https://codemirror.net/try/ so tagging as an Upstream issue

MusikAnimal changed the task status from Open to In Progress.Mon, Jul 27, 5:19 PM
MusikAnimal claimed this task.

I've filed a CodeMirror issue at https://discuss.codemirror.net/t/firefox-153-ignores-transparent-selection-styling/9838 but I do think this is likely a browser bug.

We can implement @Nardog's suggestion on Discord in the meantime: background-color: #ffffff01 !important;

gerritbot added a comment.Mon, Jul 27, 5:27 PM

Change #1318210 had a related patch set uploaded (by MusikAnimal; author: MusikAnimal):

[mediawiki/extensions/CodeMirror@master] codemirror.less: workaround for transparent selection style in FF

https://gerrit.wikimedia.org/r/1318210

gerritbot added a project: Patch-For-Review.Mon, Jul 27, 5:27 PM
gerritbot added a comment.Tue, Jul 28, 11:32 PM

Change #1318210 merged by jenkins-bot:

[mediawiki/extensions/CodeMirror@master] codemirror.less: workaround for transparent selection style in FF

https://gerrit.wikimedia.org/r/1318210

ReleaseTaggerBot added a project: MW-1.47-notes (1.47.0-wmf.14; 2026-08-04).Wed, Jul 29, 12:00 AM
Maintenance_bot removed a project: Patch-For-Review.Wed, Jul 29, 12:30 AM
TechnoSquirrel69 subscribed.Wed, Jul 29, 4:18 AM
MusikAnimal closed this task as Resolved.Wed, Jul 29, 11:30 PM
MusikAnimal moved this task from Bugs to Done on the MediaWiki-extensions-CodeMirror board.
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