Target is getting nervous, for the first time in a while. Some Target shoppers are browsing comfortably in the company’s high-design stores, then closing the deal online with lower-priced vendors. It’s enough of a phenomenon that CEO Gregg Steinhafel recently penned a letter to his suppliers with a competitive battle cry: “we aren’t willing…to let online-only retailers use our brick-and-mortar stores as a showroom.”