William Gluckin & Co. v. Int'l. Playtex Corp., 407 F.2d 177 (2d Cir. 1969), is an opinion upholding the issuance of a preliminary injunction against Playtex, manufacturer of, ahem, ladies' support garments, prohibiting Playtex from prosecuting a lawsuit it had filed against Woolworth & Co. for selling brassieres manufactured by Gluckin at Woolworth's stores in Georgia. See, what happened was this: Playtex had a patent, and Gluckin (allegedly) infringed the patent and sold the infringing unmentionables to Woolworths, who sold lots of them in Georgia. Woolworth's, Playtex, and Gluckin were all New York corporations amenable to suit in New York, but Gluckin was not amenable to suit in Georgia. Playtex sued Woolworth's for infringing its patent in Federal court in Georgia. Gluckin found out and filed their own suit (for a declaratory judgment) in Federal court in New York.
See, if the Georgia suit went ahead, the Georgia District Court would have had to determine whether the bust supporters sold by Woolworth's indeed infringed Playtex' patent. This would be the same issue as what would have to be decided in the declaratory judgment action in New York. So if the Georgia court made a decision on the subject, that decision would have had a binding effect on the New York court under the doctrine of res judicata. (Woolworth's probably could have had the Georgia case dismissed for failure to join a necessary party who could not subsequently be joined because of a lack of personal jurisdiction, see Fed. R. Civ. P. 19, but that's not what happened.)
Gluckin, therefore, really wanted to make sure it had the opportunity to litigate the patent infringement issue itself in the New York suit, and not by proxy through Woolworth's in the Georgia suit. But ordinarily, the suit that gets filed first gets priority, and later suits get enjoined until earlier ones get finished.
Fortunately for Gluckin, there is an exception to this first-filed-goes-first rule, arising out of patent law. An infringement suit against a customer of a manufacturer always has the manufacturer as the real party in interest, and the policy of the Second Circuit is to place preference on the real party in interest litigating his own claim, so long as it is more convenient than the customer suit. Which is why Gluckin got the injunction against the Georgia suit.
Anyway, I'm sure all you peoples out there who don't care about civil procedure were bored to tears reading about all that.
On a more entertaining note, reading this case reminded me of this fun yet highly inaccurate account of the invention and patenting of the brassiere from the ultra-tear-jerker film Beaches, starring Bette Midler and some other people whose names I cannot remember.