While during a call, I open the phonebook/ any window, it does not remain on the phone and vanishes. Let me explain.....if I am on a call and want to see the phonebook and move back the phone towards my ear and then see it, the phonebook screen vanishes!!! How can anybody read out any phone number/message when the screen vanishes when you cover the light sensor??? Is anyone facing this problem? Request for help.....thanks.