Default Screen turns on when using wallet case

Hey.
Im using a v10 original rom (the only one that haves hebrew) and im using a wallet case. Whenever im fliping the case, the sceen turnes on, and whenever im fliping it 180 the car mode is turning.
Normally i wounld care, but its a phone for my mom, and when she reciving a call, the call is always goes to the top bar ( you need to scroll down and click on the call , then click answer) . what sensor is doing this? How can i disable it?
Thanks.

Sent from my Nexus 4 using xda app-developers app
Google Nexus S --> Google Galaxy Nexus --> Google Nexus 4 !