I'm always a bit sad when one of my favorite restaurants is sold, and I'm always a little reluctant to head back to it and see if the new proprietors have (a) changed nothing or (b) changed everything. I'm always caught in a dilemma: On the one hand, I want it to stay the same. But shouldn't a restaurant reflect the personalities now running it? So I was more than a little relieved to discover that Bistro Zenith (3011 Yamato Rd., Boca Raton, 561-997-2570), which had been sold last year, was both familiar and innovative. A completely revamped menu offers down-to-earth meatloaf next to delectable items like seafood gnocchi bolognese, and the atmosphere is as cheerful as ever. All of which means that Bistro Zenith is still, despite the sale, living up to its name.