Mark Morris’s new—what to call it?—opera, dance, Gesamtkunstwerk, which had its New York premiere last weekend at the White Light Festival, strikes me as his best work of the decade. I hesitate to go out on a limb like this, because Morris is so notoriously eager to violate expectations that he may well come up with something better next week, just to put me in the wrong. But I have to say that, at least since about 2010, I have not seen any new piece, by any choreographer, that moved me more than Layla and Majnun.