The editor should be loaded with a "box" element that contains multiple "slots" in which user can edit content.
An additional converter adds "data-insert-count" attribute to view elements to show when it was rendered. It is displayed with a CSS at the top-right corner of rendered element. If a view element was not re-rendered this attribute should not change. Note: it only acts on "insert" changes so it can omit attribute-to-element changes or insertions not passed through dispatcher.
Observe which view elements are re-rendered when using UI-buttons:
Box title - updates title attribute which triggers re-rendering of a "box".Box author - updates author attribute which triggers re-rendering of a "box".+ - adds "slot" to box" which triggers re-rendering of a "box".- - removes "slot" from box" which triggers re-rendering of a "box".