It’s been 11 years since the America Invents Act was signed into law. Courts are still trying to make sense of one of the few provisions of the law that is favorable to patent owners.

On Tuesday, the U.S. Supreme Court asked Solicitor General Elizabeth Prelogar’s office to advise on how big a bite the America Invents Act’s estoppel provision ought to take out of future patent infringement cases. The court made the request in Apple v. California Institute of Technology.