The region has lost three more restaurants: San Francisco Oven downtown, and Grace Diner and Tria Grill in Powell. A note on the door at San Francisco Oven says to look for a new concept to open soon in the same space. Pat Petty, owner of Grace Diner, said he shuttered the breakfast-and-lunch spot closed a couple of weeks ago but is negotiating with a prospective buyer. Attempts to reach Tria owners have been unsuccessful. The place has been closed during regular business hours on a couple of visits.