--- a/src/pyams_zmi/site.py	Tue Oct 11 17:17:18 2016 +0200
+++ b/src/pyams_zmi/site.py	Tue Nov 15 10:45:45 2016 +0100
@@ -160,9 +160,9 @@
     def updateWidgets(self, prefix=None):
         super(BackOfficePropertiesEditForm, self).updateWidgets(prefix)
         if 'login_header' in self.widgets:
-            self.widgets['login_header'].label_css_class = 'textarea'
+            self.widgets['login_header'].widget_css_class = 'textarea'
         if 'login_footer' in self.widgets:
-            self.widgets['login_footer'].label_css_class = 'textarea'
+            self.widgets['login_footer'].widget_css_class = 'textarea'
 
 
 @view_config(name='back-office-properties.json', context=ISiteRoot, request_type=IPyAMSLayer,