- Cross-Appeal Rule: Must Cross Appeal If Seek To Lessen Rights Of Adversary Or Enlarge Own Rights: Where patent owner appeals from judgment of no-infringement and “not invalid,” the patent challenger must cross appeal the “not invalid” judgment or else forfeit right to challenge validity on remand, even if claims construed more broadly on appeal. Lazare Kaplan (Fed. Cir. 04/19/13) (2-1) (“a party must file a cross-appeal if, although successful in the overall outcome in the district court, the party seeks, on appeal, to lessen the rights of its adversary or to enlarge its own rights”).