Question [Q]S-view case on note 3 mystery ?

Hello,
I recently bought an S-view case for my note 3, and I have been wondering how it works. I was wondering how the finger detection works through the window (and more specifically why it doesn't work on Cm based roms) as well as how the cose/open detection woks. It's obviously not proximity, and I checked with a few apps, and a magnet, and there dose not seem to be a magnet inside the case either.
If anyone can enlighten me on either of these issues, I would be truely grateful.
Thanks!