docs: def on_tab_close_clicked(self, event, state_m):
          """Triggered when the states-editor close button is clicked
  
          Closes the tab.
  
          :param state_m: The desired state model (the selected state)
          """
          [page, state_identifier] = self.find_page_of_state_m(state_m)
          if page:
              self.close_page(state_identifier, delete=False)