How does the KOReader Evernote plugin work?

I can't find a way in KOReader to add any note to a book. The option to "Add Note" when you select a block of text is grayed out. So I assume the Evernote plugin that lets you export notes, must be for exporting existing notes added to a book by Kobo.

So I went into a book in Kobo, added a few notes. Then I went back into KOReader, open the same book, and hit Evernote | Export notes. It does create a node for that book in my Evernote account, but there is no content of the individual notes copied over.

Any idea how this plugin is supposed to work?