--- a/src/pyams_thesaurus/zmi/term.py	Tue Nov 15 10:41:35 2016 +0100
+++ b/src/pyams_thesaurus/zmi/term.py	Tue Nov 15 10:42:18 2016 +0100
@@ -73,9 +73,11 @@
     def updateWidgets(self, prefix=None):
         super(ThesaurusTermAddForm, self).updateWidgets(prefix)
         for name in ('definition', 'note'):
-            self.widgets[name].label_css_class = 'input textarea'
+            if name in self.widgets:
+                self.widgets[name].widget_css_class = 'input textarea'
         for name in ('generic', 'associations', 'usage'):
-            self.widgets[name].thesaurus_name = self.context.name
+            if name in self.widgets:
+                self.widgets[name].thesaurus_name = self.context.name
 
     def create(self, data):
         return ThesaurusTerm(data.get('label'))
@@ -147,11 +149,14 @@
         super(ThesaurusTermEditForm, self).updateWidgets(prefix)
         thesaurus = get_parent(self.context, IThesaurus)
         for name in ('definition', 'note'):
-            self.widgets[name].label_css_class = 'input textarea'
+            if name in self.widgets:
+                self.widgets[name].widget_css_class = 'input textarea'
         for name in ('generic', 'specifics', 'associations', 'usage', 'used_for'):
-            self.widgets[name].thesaurus_name = thesaurus.name
+            if name in self.widgets:
+                self.widgets[name].thesaurus_name = thesaurus.name
         for name in ('specifics', 'used_for', 'extracts', 'created'):
-            self.widgets[name].mode = DISPLAY_MODE
+            if name in self.widgets:
+                self.widgets[name].mode = DISPLAY_MODE
 
     def update_content(self, content, data):
         term = self.context