Issues right now:
- Different set of elements (e.g. #contentSub is shown in read mode, but not in edit mode. The same goes for TOC, though we do account for that one).
- Different offset (the toolbar is injected which causes an abrupt visual shift).
- Different scroll offset (same as before, but applies when you open the editor when scrolled down the page, after the transition, you're looking at a potentially very different part of the document, we should preserve it or jump to the top, not leave you somewhere randomly).