Thanks @mjbvz for the quick turnaround on preserving the open attribute! I'm still a little curious about the scrolling sync: I don't see anything in #176330 that looks like it would address the issue I'm seeing "scrolling past" a collapsed <details> block where the code cursor makes the preview act as if it's much further down, seemingly by about as much as the length of the expanded <details>.

I can now leave my <details> expanded to re-enable sync'd scrolling, but I was wondering if the intent was to not change the behavior when they're closed? Or, would it be helpful if I broke that part out into a new issue?

Originally posted by @sethp in #175353 (comment)