I have a Thunderbolt. On my old DINC when I made a call the screen would lock automatically when i held it to my ear (vertical), that doesn't happen on the Thunderbolt. Looked in the settings but can't find anything. The proximity sensor seems to be working. Any ideas what's up?? I'm constantly ending calls and hitting other buttons when I talk on the phone. To avoid this I've set the screen lock to 15 secs, but it's a hassle since it locks when I'm using other functions.