I have searched for this, so pardon me if this has already been discussed in this forum. I have noticed the phone go into like a sleep mode, maybe? I have the wifi sleep policy set to never. The signal bars go to a grey color when the phone hasn't been used or isn't really needing data? I just know that I was messing around with it, and going from screen to screen to app drawer, and it remained grey, it was when I opened the browser that both the wifi signal bars and the carrier signal bars turned green again. If someone could explain this to me that would be great!