On beta 3 here and was just setting an inline menu to be hidden in first 3 breakpoints/shown in largest 2. And a collapsed menu with the opposite visibilities. When I switch my preview size from largest to the second-largest the changeover happens right away.
On the front end my breakpoints take effect at the correct points - it’s just the admin preview that’s weird
It gets weirder. On a hunch I decided to try using Chrome instead of Safari and everything works fine.
Thanks! It’s probably something with how matchMedia works in Safari but I’m not sure just yet. We’ll check into it.