Detaching a frame should bypass it's cached permissionclient state in StorageAreaProxy. On success, you will see a series of "PASS" messages, followed by "TEST COMPLETE". PASS storage.length threw exception SecurityError: Failed to read the 'length' property from 'Storage': access is denied for this document.. PASS storage.getItem('foo') threw exception SecurityError: Failed to execute 'getItem' on 'Storage': access is denied for this document.. PASS storage.setItem('foo', 'bar') threw exception SecurityError: Failed to execute 'setItem' on 'Storage': access is denied for this document.. PASS storage.key(0) threw exception SecurityError: Failed to execute 'key' on 'Storage': access is denied for this document.. PASS storage.clear() threw exception SecurityError: Failed to execute 'clear' on 'Storage': access is denied for this document.. PASS successfullyParsed is true TEST COMPLETE