I went for a midnight coffee to Tsui Wah Restaurant, a Cantonese chain on the Fumin Lu - Changle Lu corner with Cantina Agave and a few other restaurants. It was pretty full with late night snackers, surprisingly of many ages. They have a nice HK menu, which I am sure I will try some time. The special tea is interesting - never tried it before, mix of coffee and tea... not sure how I feel about it but interesting.
291 Fumin Road, Xuhui District, Shanghai