In Hunter Douglas, Inc. v. Harmonic Design, Inc. (Fed. Cir. 1998) 153 F.3d 1318, the plaintiff sued its competitors in the field of motorized window shades--the patentee (Harmonic), and two parties holding licenses from the patentee. ( Hunter Douglas, supra, 153 F.3d at p. 1321.) The plaintiff sought a declaratory judgment of noninfringement and a determination that one of the defendant's patents were invalid or unenforceable; it also alleged state law claims, including claims for injurious falsehood and for violation of Business and Professions Code section 17200. (Hunter Douglas, at p. 1322.) It alleged that the defendants knew or should have known that the Harmonic patents were invalid, and that the defendants " 'falsely and recklessly asserted title to public property,' ... 'thereby slandering and injuring' Hunter Douglas's rights." (Ibid.) The court concluded that the claim for declaratory relief was not maintainable because it did not satisfy the "actual controversy" requirement of the federal Declaratory Judgment Act, section 2201(a) of title 28 of the United States Code. (Hunter Douglas, supra, 153 F.3d at pp. 1325-1328.) The circuit court then considered the jurisdictional challenge to the plaintiff's pendent state law claims. Citing Christianson, it concluded that the plaintiff's injurious falsehood claim was an action "arising under" federal patent law. (Hunter Douglas, supra, 153 F.3d at p. 1329.) It reasoned that a requisite element of the claim, falsehood, depended upon resolving federal patent law questions, namely, whether Harmonic's patents were invalid or whether all of its claims were unenforceable. (Ibid.) The court reasoned further that all theories of the injurious falsehood claim "depended on resolving a question of federal patent law, because Hunter Douglas did not plead, in its complaint, any other basis for a falsity on the Defendants' part. " (Ibid.) The court in Hunter Douglas noted that, following the Supreme Court's decision in Christianson, the Federal Circuit had held that at least four patent issues were of sufficient substantiality to satisfy the "arising under" jurisdictional test: (a) infringement; (b) inventorship issues; (c) attorney's fees requests under section 285 of title 35 of the United States Code; and (d) the revival of an unintentionally abandoned patent application (35 U.S.C. 41, 133), or the right to file a continuation application (35 U.S.C. 120). ( Hunter Douglas, supra, 153 F.3d at p. 1330.) The court indicated that it saw no reason to treat questions of a patent's validity and enforceability in a manner different from infringement issues. ( Id. at pp. 1330-1331.) The Hunter Douglas court therefore held "that the questions of federal patent law--validity and enforceability--were 'substantial' enough to convey section 1338(a) jurisdiction." ( Id. at p. 1329.)