public function onDisplayTool(OpenAdministrationToolEvent $event)
    {
        $iconSets = $this->iconSetManager->listIconSetsByType(IconSetTypeEnum::RESOURCE_ICON_SET);

        // TODO : do it front side
        $iconSetChoices = [];
        foreach ($iconSets as $set) {
            $iconSetChoices[$set->getName()] = $set->getName();
        }

        $content = $this->templating->render(
            'ClarolineCoreBundle:administration:appearance.html.twig', [
                'context' => [
                    'type' => Tool::ADMINISTRATION,
                ],
                'parameters' => $this->serializer->serialize(),
                'iconSetChoices' => $iconSetChoices,
            ]
        );

        $event->setResponse(new Response($content));
        $event->stopPropagation();
    }