The 5th District Appellate Court recently held that, to trigger the duty of an umbrella insurer to “drop down” and defend the insured, the insurer must have actual evidence of the exhaustion of the aggregate limits of the underlying insurance policy.The umbrella insurer in Sinclair Oil Corp. v. Allianz Underwriters Insurance Co., 2015 IL App (5th) 140069 (April 7, 2015) was represented by DeFranco & Bradley P.C. of Fairview Heights and BatesCarey LLP. Cook, Ysursa, Bartholomew, Brauer & Shelvin Ltd. of …