--- a/src/pyams_portal/zmi/portlet.py	Thu Aug 30 10:09:00 2018 +0200
+++ b/src/pyams_portal/zmi/portlet.py	Mon Sep 03 16:46:31 2018 +0200
@@ -143,6 +143,12 @@
                 })
                 output.setdefault('events', []).append(
                     get_json_widget_refresh_event(self.context, self.request, get_form_factory, 'renderer'))
+                output['smallbox'] = {
+                    'status': 'info',
+                    'message': self.request.localizer.translate(_("You changed renderer selection. Don't omit to "
+                                                                  "update new renderer properties...")),
+                    'timeout': 5000
+                }
         return output