When I use the approach above, it LOOKS like things are working in the editor, but if you publish the page and view it, none of the default colors are applied. I put this document together to help illustrate and explain: https://docs.google.com/document/d/1VJmUCFFGRieIgkJ4Jj0PZiRefCrJQr2EUbBlzaBsPb0/edit
Same issue, but the problem appears to be larger than just not having the “Update” button be clickable. If I mess around in a core widget block, yes I can have the “Update” button be clickable again, but it doesn’t actually SAVE any of my changes in my ACF block (but the changes to the core block are updated).
Gah – of course, after submitting, I see how unclear the title was. It should read: Limit which TAXONOMIES users can filter by…