Home furnishing retailers stumbled Thursday on the heels of Williams-Sonoma’s (WSM) weak third-quarter guidance. The group, down 3%, was one of the session’s biggest losers. Prior to Thursday’s slide, it ranked No. 56 among the 197 industry groups tracked by IBD. Williams-Sonoma — which owns the second best Composite Rating in the 13-stock group — plunged 12% in the highest volume of its two-year advance.