My soon to be former coworker does that too, all day long. So, as I'm trying to show her how to do something or explain something to her, she's messing with her blackberry. MAKES ME INSANE and my boss called her out on it during her eval. It didn't change though. Then she doesn't remember what I showed her and screws it up when she has to do it on her own. I'm so glad she's leaving in two months.