public function getItems()
    {
        if ($this->_items !== null) {
            return $this->_items;
        }
        
        $data = [];
        foreach ($this->getModules() as $node) {
            foreach (ArrayHelper::getValue($this->getModuleItems($node['id']), 'groups', []) as $groupValue) {
                foreach ($groupValue['items'] as $array) {
                    $array['module'] = $node;
                    $data[] = $array;
                }
            }
        }

        $this->_items = $data;
        
        return $data;
    }