We have a magic keyword -moz-anchor-decoration for text-decoration-line that, it would reset text-decoration-line to none if user sets the preference to not underline links. This was added in bug 57757, but it is not clear why it is still needed, since it seems user pref stylesheet is enabled everywhere.

Comment on attachment 8857829 [details] Bug 1355734 - Remove text-decoration-line: -moz-anchor-decoration. https://reviewboard.mozilla.org/r/129848/#review132418 ::: commit-message-5e37b:1 (Diff revision 1) > +Bug 1355734 - Remove text-decoration-line: -moz-anchor-deciration. r?masayuki,heycam -moz-anchor-decoration

Comment on attachment 8857829 [details] Bug 1355734 - Remove text-decoration-line: -moz-anchor-decoration. https://reviewboard.mozilla.org/r/129848/#review132456 This isn't enough to remove the feature entirely. You need to remove nsPresContext::mUnderlineLinks and kPresContext_UnderlineLinks. Additionally, you need to remove the pref from all.js and setting UI in color.xul. I wonder, did you talk about this to Thunderbird and SeaMonkey people? At least, you should notify them of this bug.

CCing :jaws who manages preference UI. And I'd be happy if you'd add example of the user stylesheet into the commit message.

I'm not removing the underline link feature. I'm only removing the magic keyword, which, I believe, is no longer necessary for that feature.

And the reason it's not necessary is that we take it into account when building the pref style sheet: http://searchfox.org/mozilla-central/rev/944f87c575e8a0bcefc1ed8efff10b34cf7a5169/layout/style/nsLayoutStylesheetCache.cpp#924-929

Comment on attachment 8857829 [details] Bug 1355734 - Remove text-decoration-line: -moz-anchor-decoration. https://reviewboard.mozilla.org/r/129848/#review132460 Ah, I see.

We're sorry, Autoland could not rebase your commits for you automatically. Please manually rebase your commits and try again. hg error in cmd: hg rebase -s 889991bbb65c -d 2df7d0984161: rebasing 389599:889991bbb65c "Bug 1355734 - Remove text-decoration-line: -moz-anchor-decoration. r=heycam,masayuki" (tip) merging layout/style/test/stylo-failures.md warning: conflicts while merging layout/style/test/stylo-failures.md! (edit, then use 'hg resolve --mark') unresolved conflicts (see hg resolve, then hg rebase --continue)

Pushed by xquan@mozilla.com: https://hg.mozilla.org/integration/autoland/rev/52ba40a2c133 Remove text-decoration-line: -moz-anchor-decoration. r=heycam,masayuki

(In reply to Kohei Yoshino [:kohei] from comment #13) > https://developer.mozilla.org/en-US/docs/Web/CSS/text-decoration-line I've deleted it from the reference page, and also added a note to the Fx55 rel notes: https://developer.mozilla.org/en-US/Firefox/Releases/55#Removals_from_the_web_platform