The section headers get removed from the content and placed in the section events' "title" tag, with discrete headers untouched.
We lazy-load the sections, as you scroll down and as you open up levels in the ToC. We therefore have to handle someone opening up a level in the ToC, that hasn't been loaded into the reading panel, already, like a fast-forward viewer, but just of that section. The sections inbetween get filled in, as they scroll toward the already-renderd sections.
Or something like that. I think. 😂🤷🏻♀️