"Shared books are in a Calibre library" not working

I use ubooquity to access a library on my ereader. This library is managed with calibre. Ubooquity has an advanced option called "Shared books are in a Calibre library", but either this is not working for me or I misunderstand what it does.

What I understand is, that with this option enabled ubooquity should skip the book folder that is created bei calibre. So when I click an author I should see all their books and with another click I should see the details. But with or without this option enabled, when I click an author I see the folders and it needs another click to actually see the book. What do I miss here?

Edit: Nevermind. I noticed it worked with books I added after I set this option. I cleared the database and after a rescan it works as expected. But maybe this should be added to the tooltip.