I've made numerous highlights in many books, but now I've discovered that all the highlights have been saved into one of the default documents (Solid Colors / Emphasis MarkUp / Highlighter Pens).
I now know how to set the default highlighting so that it saves into a document for each specific resource, going forward.
How can I reassign my older highlights into their specific resource?
Is there a way of doing this other than going through every highlight in each book individually (literally thousands to edit)?