--- a/src/pyams_default_theme/features/menu/portlet/navigation/__init__.py	Wed Dec 12 10:17:05 2018 +0100
+++ b/src/pyams_default_theme/features/menu/portlet/navigation/__init__.py	Wed Dec 12 11:15:25 2018 +0100
@@ -13,7 +13,7 @@
 __docformat__ = 'restructuredtext'
 
 from persistent import Persistent
-from zope.interface import implementer, Interface
+from zope.interface import Interface
 from zope.location.location import Location
 from zope.schema.fieldproperty import FieldProperty
 
@@ -104,7 +104,6 @@
 # Double navigation portlet "double-select" renderer
 #
 
-@implementer(IDoubleNavigationPortletSelectMenusRendererSettings)
 @factory_config(provided=IDoubleNavigationPortletSelectMenusRendererSettings)
 class DoubleNavigationPortletSelectMenusRendererSettings(Persistent, Location):
     """Double navigation portlet select menus renderer settings"""

--- a/src/pyams_default_theme/features/search/portlet/__init__.py	Wed Dec 12 10:17:05 2018 +0100
+++ b/src/pyams_default_theme/features/search/portlet/__init__.py	Wed Dec 12 11:15:25 2018 +0100
@@ -32,7 +32,6 @@
 from pyams_default_theme import _
 
 
-@implementer(ISearchResultsPortletDefaultRendererSettings)
 @factory_config(provided=ISearchResultsPortletDefaultRendererSettings)
 class SearchResultsPortletDefaultRendererSettings(Persistent, Contained):
     """Search results portlet default renderer settings"""

--- a/src/pyams_default_theme/shared/view/portlet/__init__.py	Wed Dec 12 10:17:05 2018 +0100
+++ b/src/pyams_default_theme/shared/view/portlet/__init__.py	Wed Dec 12 11:15:25 2018 +0100
@@ -14,7 +14,7 @@
 
 from persistent import Persistent
 from zope.container.contained import Contained
-from zope.interface import Interface, implementer
+from zope.interface import Interface
 from zope.schema.fieldproperty import FieldProperty
 
 from pyams_content.shared.view.portlet.interfaces import IViewItemsPortletSettings
@@ -30,7 +30,6 @@
 
 
 @factory_config(provided=IViewItemsPortletVerticalRendererSettings)
-@implementer(IViewItemsPortletVerticalRendererSettings)
 class ViewItemsPortletVerticalRendererSettings(Persistent, Contained):
     """View items portlet renderer settings"""