I'm asking for a friend who owns this phone. Can anyone share some insight so I can pass on the info to her? Thanks. Her exact words to me today were: "I need to know how to shut the screen off on my xperia x10 during a call...sometimes it shuts off, sometimes it doesn't...when it doesn't, it causes me to perform a TON of unwanted tasks like adding a contact, changing the wallpaper, etc. when it hits my cheek." Thanks again!