docs: def set_enabled(self, on, text=None):
          """ Set the default input or deactivated (disabled) style scheme
  
          The method triggers the signal 'changed' by using set_text. Therefore, the method use the while_in_set_enabled
          flag to make activities of the method observable. If a method trigger this method and was triggered by a
          changed-signal this flag is supposed to avoid recursive calls.
  
          :param bool on: enable flag.
          :param str text: optional text to insert.
          :return:
          """
          self.while_in_set_enabled = True
  
          # Apply color scheme by set text 'workaround' (with current buffer source)
          self.set_text(self.get_text()) if text is None else self.set_text(text)
  
          if on:
              self.textview.set_editable(True)
              self.apply_tag('default')
          else:
              self.apply_tag('deactivated')
          self.textview.set_editable(on)
          self.while_in_set_enabled = False