--- a/src/pyams_workflow/zmi/transition.py	Tue Nov 15 10:44:51 2016 +0100
+++ b/src/pyams_workflow/zmi/transition.py	Tue Nov 15 10:45:15 2016 +0100
@@ -61,7 +61,7 @@
             self.widgets['transition_id'].mode = HIDDEN_MODE
             self.widgets['transition_id'].value = self.request.params.get('form.widgets.transition_id')
         if 'comment' in self.widgets:
-            self.widgets['comment'].label_css_class = 'textarea'
+            self.widgets['comment'].widget_css_class = 'textarea'
 
     def updateActions(self):
         super(WorkflowContentTransitionForm, self).updateActions()