I wonder whether that font declaration in Common.css still required -- is ULS already able to handle that?

nzmoihue wrote:

That is because Persian Wikipedia community wanted use the non-free font; That is long discussion and Persian users consensus was using the non-free Tahoma as first font on Windows users (long story short, because Tahoma is highly used across Persian sites and web embedded fonts having problem on rendering as they have not hinting imformation). And Persian users on other wikis http://www.wikidata.org/wiki/MediaWiki_talk:Common.css#farsi_font http://meta.wikimedia.org/wiki/MediaWiki:Common.css also wanted the same configuration with Persian Wikipedia for other wikis.

I think the main point here is CodeEditor should declare a monospace for itself, like the normal editor is doing in the same situation.

(In reply to comment #2)

I think the main point here is CodeEditor should declare a monospace for
itself, like the normal editor is doing in the same situation.

One fault in CodeEditor is that it doesn't declare the page language (which is set to English in Scribunto) to the browser. When its language attribute is correctly set to English, this issue disappears.

I'm not sure whether the normal editor explicitly set a monospace font, and I remember I saw some wiki edit boxes not using some monospace fonts. Further more, does every language / script have the concept of "monospace"?

nzmoihue wrote:

I agree but normal editor as using <textedior> with unmodified preference have
textarea {

font-family: monospace;

} (via useragent stylesheet of-course)

nzmoihue wrote:

I converted :lang(fa) to html[lang=fa] body, [lang=fa] on Wikidata and Wikimedia Commons to temporary solve the CodeEditor bug.

Relates to upstream https://github.com/ajaxorg/ace/issues/1429