Hi chaley. This is an excellent app and I use it religiously; thank you for providing it at such a low cost. I've been wondering for a little while as to whether there are any plans to integrate an ability to 'see' books inside their separate Calibre libraries within CC, and if this is even at all possible (given that programming isn't my area of expertise!).
I have three separate libraries within Calibre, and though re-tagging my books in Calibre itself is an acceptable solution for CC management, it's not as suitable as being able to switch between libraries. As I said, I don't know if this is even possible given the limitations of programming languages - but if it is, would there be a possibility of it happening in a future update?