code: def update_buttons(self):
          
          current_scheme = self.current_scheme
          names = self.get_option("names")
          try:
              names.pop(names.index(u'Custom'))
          except ValueError:
              pass
          delete_enabled = current_scheme not in names
          self.delete_button.setEnabled(delete_enabled)
          self.reset_button.setEnabled(not delete_enabled)
docs: Updates the enable status of delete and reset buttons.