public function addComponent(Doozr_Form_Service_Component_Interface_Html $element)
    {
        $index               = $this->addChild($element);
        $this->index[$index] = self::COMPONENT;

        (!isset($this->indexReverse[self::COMPONENT])) ? $this->indexReverse[self::COMPONENT] = [] : null;
        $this->indexReverse[self::COMPONENT][]                                                = $index;

        return $index;
    }