Here is a second case from the Federal Circuit,  Air Measurement Technologies v. Akin Gump, which is a more simple application of federal question jurisdiction.  Here the issue on appeal was whether the Federal District Court had subject matter jurisdiction over this non-diverse state court legal malpractice action.  District court and the Appellate Court both determined that the case involved a substantial federal question – patent law- and held that the court did indeed have jurisdiction, and that the matter was to continue in District Court and not be remanded.