[Android Central Question]

My S9 fits into my old S8 clearview case just fine (with some minor enlargements for the on button and flash.) Yay! Saved me $60!

Well almost. The S9 does not register the case at all. I tested it with an actual S9 case at T-Mobile and that worked so I know the phone is working. The front magnet is in the same place and I have tried to engage the sensor with the case magnet upside down to change the polarity. No joy.

So I assume there is another non-obvious sensor or such that tells the phone the case is installed. Any idea what this is and how it might differ between the cases?