But amid clamoring for a more flexible rule, the Federal Circuit showed Tuesday that it will allow fee-shifting when the right case comes around.

The U.S. Court of Appeals for the Federal Circuit refused to let LED lighting provider O2 Micro International off the hook for more than $9 million in attorney fees and costs. In an 18-page order, the three-judge panel affirmed a decision by U.S. District Chief Judge Claudia Wilken in Oakland to award attorney fees to Monolithic Power Systems after finding that O2 Micro had engaged in litigation misconduct and "vexatious litigation strategy" in a decade-long flurry of suits against its competitor.