Reviewed by Sam Thielman
Tina Howe's <cite>Chasing Manet</cite> almost makes you envy its mentally ill characters the good fortune of not knowing where they are. Everyone else in the theater is aware they're watching a bad example of the nursing home drama—a genre that, by definition, does not have much life left in it. With the exception of one interesting monologue, beautifully delivered by David Margulies, the play falls flat, cut o…