Hurrah. Another American museum has gotten it right, bracing against the tide of disastrous new buildings and additions that ruin and sometimes cripple so many of these institutions.

The cause for celebration is a makeover at the venerable Wadsworth Atheneum here, which opened its doors in 1844 and is this country’s oldest art museum in continuous operation. It joins a growing list of successful expansions and refurbishments that may mark the end of an era of architectural indulgence that began in 1978 with the opening of the National Gallery’s East Wing, the putative mother of useless event spaces that nourish neither art nor the people who love it.