A look at the legal dispute between Walgreens and Cooler Screens, which installed 10,000 smart doors that track shoppers and show ads at Walgreens’ US stores (Austin Carr/Bloomberg)

Austin Carr / Bloomberg:
A look at the legal dispute between Walgreens and Cooler Screens, which installed 10,000 smart doors that track shoppers and show ads at Walgreens’ US stores  —  A startup promised the pharmacy chain its high-tech coolers would track shoppers and spark an in-store ad revolution.