Trouble with Thunderbolt?
For any of you having issues with Prox on the Thunderbolt, make sure there isn’t any dust blocking the actual proximity sensor. Because of the design of the phone, dust is easily caught in there and it blocks it.
There is also a software issue that might be the culprit of Prox not working. I believe it has already been fixed, but it could still be an issue if you haven’t updated.