Opening the window does nothing interesting except to open the window.
To get information, with the window open, click on a category column (tags, series, publisher, authors, etc) on a book in the library view. Quickview will show you on the left-hand side the items in that category applied to the selected book. The first item in that list will be selected, and quickview will show you on the right-hand side all the books in your library with that item applied. Click on an different item to see all the books with that different item. Example usages: quickly seeing what other books:
- have a tag that is applied to the currently selected book,
- are in the same series
- have the same values in a custom column
- are written by one of the same authors
without changing the sort or search in the library view.
Double-click on a book to select that book in the library view. This will also change the items display (the left-hand side) to show the items in the newly-selected book.
Shift- (or Ctrl-) double-click on a book to select that book in the library view and then open the edit metadata dialog on that book.