diff -r d50743e69693 -r 7f0d72e427b1 src/pyams_content/shared/form/zmi/field.py
--- a/src/pyams_content/shared/form/zmi/field.py	Thu Jul 12 17:35:51 2018 +0200
+++ b/src/pyams_content/shared/form/zmi/field.py	Thu Jul 12 18:18:15 2018 +0200
@@ -243,11 +243,6 @@
     fields = field.Fields(IFormField).omit('__parent__', '__name__', 'visible')
     edit_permission = MANAGE_CONTENT_PERMISSION
 
-    def updateWidgets(self, prefix=None):
-        super(FormFieldAddForm, self).updateWidgets(prefix)
-        if 'description' in self.widgets:
-            self.widgets['description'].widget_css_class = 'textarea'
-
     def create(self, data):
         return FormField()
 
@@ -290,8 +285,6 @@
         super(FormFieldPropertiesEditForm, self).updateWidgets(prefix)
         if 'name' in self.widgets:
             self.widgets['name'].mode = DISPLAY_MODE
-        if 'description' in self.widgets:
-            self.widgets['description'].widget_css_class = 'textarea'
 
     def get_ajax_output(self, changes):
         output = super(self.__class__, self).get_ajax_output(changes)