Illinois courts estop liability insurers that neither defend potentially covered actions nor timely seek a declaration of their obligations from disputing coverage. Although the Illinois Supreme Court has not articulated the precise standard for timeliness under this rule, the “appellate court seems to have settled on the ‘reasonable time’ test … to measure an insurer’s timeliness when filing a declaratory action.” Navigators Ins. Co. v. Shimkus, No. 07 CH 23439, 2008 WL 5743485, at III.B.1. (Cir. Ct. Cook County Nov. 14 …