Hello. I've a problem and it annoyed me. Whlie I am using phone to call or answer incoming phone call, my Mi3 screen always display nothing like the phone are in sleeping mode but I can't do anything(touch any button, open num pad. Can't do anything) until the one who I phoned or he/she hung up the phone. So may be it's a bug of new update or my phone may have cache that I should erase it first but I don't know where so can you help me please?