public function onUnregister(Model\Registry $registry)
{
parent::onUnregister($registry);
// Unregister the fallback page
if ($this->fallback && $this->type == 'root' && $registry->isRegisteredAlias($this, 'contao.dns-fallback', $this->dns)) {
$registry->unregisterAlias($this, 'contao.dns-fallback', $this->dns);
}
}