This issue only happens on site of type "blog".
The following error occurs when the selection change, by selecting the sitemap root or a page inside the sitemap :

TypeError: Cannot read property 'SurveyDAO' of undefined
at constructor._onSelectionChanged (http://localhost:8400/v4/plugins/survey/resources/js/Ametys/plugins/survey/controller/Export2HtmlActionController.js:61:21)
at constructor.fire (http://localhost:8400/v4/plugins/core-ui/resources/js/Ametys/message/MessageBus.js:166:14)
at constructor.cb (http://localhost:8400/v4/plugins/core-ui/resources/js/Ametys/message/Message.js:279:31)
at http://localhost:8400/v4/plugins/extjs6/resources/ext-all-debug.js:6711:35