Carl Maria von Weber, the early-19th-century German composer, wrote ten or so operas. But we know basically three of them, and those chiefly through their overtures, and a few arias. The operas I'm speaking of are "Der Freischütz," "Euryanthe," and "Oberon." The Salzburg Festival is performing the service of staging "Der Freischütz" this year. But it is staging it in a production that baldly subverts the opera — thereby canceling the service. "Der Freischütz" means "The Marksman," roughly, and it is a "singspiel" — an opera that combines singing and talking. It is a cousin of "The Abduction from the...