If you were at the Black Box Theatre’s opening-night presentation of You’re a Good Man, Charlie Brown, the question of precisely who stole the show shouldn’t be arguable. Terrific though they were, it wasn’t the riotously strident Becca Johnson, or Sara Tubbs and her wicked Kristin Chenoweth impersonation, or third-grader Makenna Miller in costumer Kris Castel’s Big-Bird-meets-Carol-Channing feathers – or any other members of directors David Miller’s and Gary Clark’s appealing cast. It was the grade-school attendees whose infectious laughs frequently punctuated images and gags, and made the show even more of a charmer than it already was.