I'd probably evaluate my behavior to see if, in fact, I am giving the other child (A) more attention for his negative behavior than I am giving to this child (B) for his positive behavior.
I don't always get it right. Sometimes I watch my tapes to get another view of my actions. Self-evaluation is helpful.
I held my hand over my mouth way too much last week, this week many of the kids are doing it and I can't understand half of what they are saying. It was becoming a habit I was unaware of.
I have been rearranging the playroom and considering new layouts. Apparently, when I am in deep thought or reading I now do this.
So am working to stop it (huge flu season risk, ack!!).
Kids are great barometers and parrots of behavior.