--- a/src/pyams_portal/portlet.py	Mon Jul 09 13:42:42 2018 +0200
+++ b/src/pyams_portal/portlet.py	Tue Jul 10 08:50:36 2018 +0200
@@ -190,6 +190,8 @@
 
     weight = 0
 
+    resources = ()
+
     @property
     def slot_configuration(self):
         template = IPortalPage(self.context).template
@@ -201,6 +203,11 @@
     def renderer_settings(self):
         return IPortletRendererSettings(self.settings)
 
+    def update(self):
+        super(PortletRenderer, self).update()
+        for resource in self.resources:
+            resource.need()
+
     def render(self):
         preview_mode = self.request.annotations.get(PREVIEW_MODE, False)
         if preview_mode or not self.use_portlets_cache: