--- a/src/pyams_viewlet/manager.py	Fri Jan 18 10:22:33 2019 +0100
+++ b/src/pyams_viewlet/manager.py	Fri Jan 18 10:23:14 2019 +0100
@@ -12,27 +12,24 @@
 
 __docformat__ = 'restructuredtext'
 
-
-# import standard packages
 import logging
-logger = logging.getLogger('PyAMS (viewlet)')
 
 import venusian
-
-# import interfaces
-from pyams_viewlet.interfaces import IViewletManager, IViewlet
+from pyramid.exceptions import ConfigurationError
+from pyramid.httpexceptions import HTTPUnauthorized
 from pyramid.interfaces import IRequest, IView
+from pyramid.threadlocal import get_current_registry
 from zope.component.interfaces import ComponentLookupError
 from zope.contentprovider.interfaces import BeforeUpdateEvent
+from zope.interface import Interface, classImplements, implementer
 from zope.location.interfaces import ILocation
 
-# import packages
 from pyams_template.template import get_view_template
 from pyams_utils.request import check_request
-from pyramid.exceptions import ConfigurationError
-from pyramid.httpexceptions import HTTPUnauthorized
-from pyramid.threadlocal import get_current_registry
-from zope.interface import implementer, classImplements, Interface
+from pyams_viewlet.interfaces import IViewlet, IViewletManager
+
+
+logger = logging.getLogger('PyAMS (viewlet)')
 
 
 @implementer(IViewletManager)
@@ -101,20 +98,19 @@
 
     def update(self):
         """See zope.contentprovider.interfaces.IContentProvider"""
-        self.__updated = True
-
         # check permission
         if self.permission and not self.request.has_permission(self.permission, context=self.context):
             return
-        # Find all content providers for the region
-        viewlets = self._get_viewlets()
-        # Just use the viewlets from now on
+        # get the viewlets from now on
         self.viewlets = []
-        for name, viewlet in viewlets:
+        append = self.viewlets.append
+        for name, viewlet in self._get_viewlets():
             if ILocation.providedBy(viewlet):
                 viewlet.__name__ = name
-            self.viewlets.append(viewlet)
+            append(viewlet)
+        # and update them...
         self._update_viewlets()
+        self.__updated = True
 
     def _get_viewlets(self):
         """Find all content providers for the region"""
@@ -134,11 +130,10 @@
 
     def render(self):
         """See zope.contentprovider.interfaces.IContentProvider"""
-        # Now render the view
-        if self.permission and not self.request.has_permission(self.permission, context=self.context):
+        # Check for previous update
+        if not (self.__updated and self.viewlets):
             return ''
-        if not self.viewlets:
-            return ''
+        # Now render the view
         if self.template:
             return self.template(viewlets=self.viewlets)
         else:
@@ -207,7 +202,7 @@
 
 
 class ConditionalViewletManager(WeightOrderedViewletManager):
-    """Conditional weight ordered viewlet managers."""
+    """Conditional weight ordered viewlet managers"""
 
     def filter(self, viewlets):
         """Sort out all viewlets which are explicit not available