diff -r f933926ed0a1 -r ea722c2352b7 src/pyams_content/component/theme/zmi/manager.py
--- a/src/pyams_content/component/theme/zmi/manager.py	Wed Jul 11 10:18:10 2018 +0200
+++ b/src/pyams_content/component/theme/zmi/manager.py	Wed Jul 11 13:36:12 2018 +0200
@@ -67,6 +67,9 @@
     fields = field.Fields(ITagsManager)
     edit_permission = MANAGE_SITE_ROOT_PERMISSION
 
+    def getContent(self):
+        return ITagsManager(self.context)
+
     def updateWidgets(self, prefix=None):
         super(TagsManagerEditForm, self).updateWidgets(prefix)
         widget = self.widgets['thesaurus_name']
@@ -114,6 +117,9 @@
     fields = field.Fields(IThemesManager)
     edit_permission = MANAGE_TOOL_PERMISSION
 
+    def getContent(self):
+        return IThemesManager(self.context)
+
     def updateWidgets(self, prefix=None):
         super(ThemesManagerEditForm, self).updateWidgets(prefix)
         widget = self.widgets['thesaurus_name']
@@ -161,6 +167,9 @@
     fields = field.Fields(ICollectionsManager)
     edit_permission = MANAGE_TOOL_PERMISSION
 
+    def getContent(self):
+        return ICollectionsManager(self.context)
+
     def updateWidgets(self, prefix=None):
         super(CollectionsManagerEditForm, self).updateWidgets(prefix)
         widget = self.widgets['thesaurus_name']