protected function getItemRequestHandler($gridField, $record, $requestHandler)
    {
        $class = $this->getItemRequestClass();
        $assignedClass = $this->itemRequestClass;
        $this->extend('updateItemRequestClass', $class, $gridField, $record, $requestHandler, $assignedClass);
        /** @var GridFieldDetailForm_ItemRequest $handler */
        $handler = Injector::inst()->createWithArgs(
            $class,
            array($gridField, $this, $record, $requestHandler, $this->name)
        );
        if ($template = $this->getTemplate()) {
            $handler->setTemplate($template);
        }
        $this->extend('updateItemRequestHandler', $handler);
        return $handler;
    }