Just out of curiosity has anyone else had any issues with the proximity sensor on their white iPhone, my wife is on her 3rd phone in 5 days, the 1st one's sensor didn't work at all and the 2nd one was hit and miss, sometimes it worked and sometimes it didn't..... I've had my black iPhone 4 for over 3 months without any issues whatsoever... So any feedback would be great, thanks....