Post

@localghost.dev

I'm not sure if it's because I have a lot of CSS custom properties (not that many in the grand scheme of things) but I'm finding in Firefox Dev Tools changing the values of custom properties doesn't seem to do anything any more. Anyone else?

@jakearchibald.com

Ohhh can you give me a URL and some steps to reproduce what you're seeing?

@localghost.dev

Hiya! I've just had another look and it's not the custom properties any more (a browser restart fixed that) but on localghost.dev?theme=city trying to change the colour of the `[data-theme="city"] .content h1` is not working - I think it might be the data attribute?

7/6/26, 5:38 pm0 reposts2 likes

@jakearchibald.com

Taaaaa! I've set a reminder to dig into this tomorrow morning.

@tristan-f.bsky.social

If it helps, I've been nerd-sniped and it seems it's caused by the 🔗 emoji and the [] attribute selector on the same line: jsfiddle.net/3kmh058o/

@localghost.dev

Well figured out!

Nicolas Chevobbe

@nicolaschevobbe.bsky.social

this just got fixed in bugzilla.mozilla.org/show_bug.cgi... , which should be in tomorrow's @firefoxnightly.bsky.social and in Firefox 153

bugzilla.mozilla.org2045645 - Cannot change styles of an element due to an emoji on the same line of CSSRESOLVED (nchevobbe) in DevTools - Inspector. Last updated 2026-06-11.

@tristan-f.bsky.social

Turns out it's not that emoji in particular, but any 4 byte character will repro.

@jakearchibald.com

Yep! And it doesn't need to be in a property value either. Fun one! Filed bugzilla.mozilla.org/show_bug.cgi...

bugzilla.mozilla.org2045645 - Cannot change styles of an element due to an emoji on the same line of CSSNEW (nobody) in DevTools - Inspector. Last updated 2026-06-08.