A preliminary determination on whether an Illinois “door closing statute” blocked companies incorporated in Pennsylvania and Israel from pursuing a diversity claim in Chicago — because they weren’t registered under the Illinois Business Corporation Act — required subtle, extensive analysis.Israel-based Salzman Group Ltd. and Pennsylvania-based Bracken Data Inc. used diversity jurisdiction to sue Thomas Guel and Ellie Pharmaceuticals in the Dirksen Courthouse for alleged breach of contract.Each agreement had a choice of law …