One of the biggest complaints about the iPhone 4 has been the proximity sensor issue, in which the phone goes visually berserk during a phone call as if it cannot decide whether your face is next to the phone or not. It is a royal pain when you want to hang up the phone or switch to speaker mode or select the menu for the numbers screen. It has been 5 months since the release of the iPhone and this has not been corrected. Personally, I think that this should have been sent as an update.
I have found a way to make the screen stay on. I am using this method now until iOS 4.2 shows up some time in the future as promised. The solution is this: Keep your thumb pressed on the HOME button during the phone call when you want to press any of the following buttons - Speaker, Keypad, Mute, FaceTime, Contacts or Add Call. It seems that whatever software short circuit that exists is corrected with this maneuver. Until Apple comes out with the updated iOS, this is as good as it gets for now.
THIS ISSUE HAS BEEN RESOLVED. SURPRISE! IT HAS NOTHING TO DO WITH APPLE, AT LEAST NOT IN MY CASE GO TO MY UPDATED POSTING ON THIS ISSUE: