It's a rule: people want to enter a major public building through the front door, and they resent it when they're sent elsewhere. Years ago the Museum of Fine Arts in Montreal closed its main entrance and forced visitors through what looked like telephone booths tucked away to the sides into the basement. About the same time the Museum of Fine Arts in Boston closed its monumental entrance facing Huntington Avenue and sent visitors around the corner through the door of a hangar-like new addition. In both cases the error endured for about five years before common sense prevailed and the real front doors were re-opened. It will have taken ten years for the ROM to correct the Crystal mistake.