IF YOU WATCH people take their seats during this opening week of Wolf Trap's 15th season, you'll notice some curious group behavior. They'll find their seats, look around to see who else is there and then shoot a quick glance straight up. What are they looking for?

The crack, of course. They're searching for the 8-foot-long fissure that developed last winter in one of the beams that supports the Filene Center's soaring roof. When it was first discovered, the news was almost too painful: first the theater had been destroyed by fire, then rebuilt with a special push and pride -- and then the crack. It was like another setback to the family. This week was the first chance theatergoers had to see the terrible evidence. Fortunately, there isn't any. All has been fixed.

Still, this looking up seems to draw the audience together, in a way that not even New York City Opera can. The audience is not so much looking for reassurance that the roof won't fall -- "You got your insurance premium paid up?" some wagged -- as it is confirmation that this important part of the community has once again survived. Surely some of the applause has been continuing acknowledgment that Wolf Trap's guide and spirit, Catherine Filene Shouse, was right: people would be as eager to take the family (and a picnic) to enjoy the arts in the countryside as they would be to go out to a ballgame. That feeling of togetherness is always there at Wolf Trap, rain or shine.

Probably the only good thing to say about that infamous crack is that its timing was right. After all, it could have appeared this week. How awful it would be to blame those marvelous tenors for bringing the house down.