Bought my girl the White IPhone 4 and got her the Griffen Survivor case so nothing could happen to the phone. Problem is, the plastic screen on the case blocks the proximity sensor from working so it doesn't black out the screen when she's on a call and holding it to her face. This leads to her going into mute, hanging up on the person, etc. Very frustrating. I even put my black Verizon IPhone 4 in the case and tested the proximity sensor on my phone and it wouldn't work with mine as well. But the minute I take either phone out of the case, the proximity sensors work great every time! I can't believe Griffen would even sell this case knowing about this huge design flaw! This makes the case unusable, because who wants to always be risking hanging up on people because of a case? Anyone else have similar problems? Any known fixes?