Who owns what

foldkit-richtext-dom     the editor: its host element, the editable subtree, every edit
your application         every piece of state the chrome shows, and where it is drawn
foldkit-mixins-richtext  nothing: each view is a function of what it is given  (this package)

The editor renders its host and nothing else; the chrome beside it is the application's. foldkit-richtext-dom/toolbar ships plain versions of some of it, such as marksToolbar. This package draws the same chrome as slot views. It cannot wrap the plain ones, because a slot's contributions resolve at the element the view creates, so a slot view owns its elements; the two share the rules, such as markActive.