Full screen call

Hii everyone... When ever I am playing clash of clan or any other game and I receive a call at the same time and pick it up,the call goes in full screen mode and the app I am using is pushed to background... Can I know a method or is there any xpose module which can stop this from happening... I don't want the app which I am using at the moment go to background when I receive a call....
Tnx a lot...
Asus zenfone 2 (2.20.40.160)

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