Thanks for pointing out the module configuration page for JetPack, and sorry for the delay getting back to you
Fortunately, we probably don’t need JetPack – which means we are mostly reporting rather than requesting support.
But to add some more details…
When I enabled the JetPack Custom CSS module on an unrelated website (and not a multi-site), my reported issue doesn’t exist there.
And unfortunately, I can’t access the JetPack modules page using the URL heirarchy you provided on the multisite with the issue – otherwise I would have tried disabling the Custom CSS module, if only to confirm your suggested fix.
This reply was modified 3 years, 5 months ago by raccoondog.
Bravo, bcworkz – good catch! “The Advanced CSS controls” options disappeared when JetPack was deactivated, and the CSS Editor live-preview now functions as it did before.
I recall that the enable checkbox was in Dashboard > Appearance > Additional CSS > Advanced CSS controls. Yes, this anomalous “Additional CSS” was a sister to Customize. It appeared only at the root site, and not in the sub-sites, and it disappeared after “Advanced…” was enabled.
I’m not convinced that we even need JetPack. It was added by the person who installed the multisite for us. I suspect the bug appeared via an auto-update.
The problem appeared after I enabled it, but I can’t find a means to disable it. Further evidence that “Advanced” is causing the problem is that checking the “Start Fresh” box briefly restores the live-preview
FWIW, the browser console does show a difference between the root site (left) and the still fully functional CSS Editor on the sub-sites (right). But the details might not matter if I can find a way to disable the “Advanced CSS controls”.
