Iblock::resolve

public function resolve($entity)
{
	if ($entity === "catalog")
	{
		if (!$this->catalog && $this->loadFromDatabase())
		{
			if (BitrixMainLoader::includeModule('catalog'))
				$this->catalog = new ElementCatalog(0);
		}

		if ($this->catalog)
			return $this->catalog;
	}
	return parent::resolve($entity);
}