docs: def notification_selected_sm_changed(self, model, prop_name, info):
          """If a new state machine is selected, make sure the tab is open"""
          selected_state_machine_id = self.model.selected_state_machine_id
          if selected_state_machine_id is None:
              return
  
          page_id = self.get_page_num(selected_state_machine_id)
  
          # to retrieve the current tab colors
          number_of_pages = self.view["notebook"].get_n_pages()
          old_label_colors = list(range(number_of_pages))
          for p in range(number_of_pages):
              page = self.view["notebook"].get_nth_page(p)
              label = self.view["notebook"].get_tab_label(page).get_child().get_children()[0]
  
              # old_label_colors[p] = label.get_style().fg[Gtk.StateType.NORMAL]
              old_label_colors[p] = label.get_style_context().get_color(Gtk.StateType.NORMAL)
  
          if not self.view.notebook.get_current_page() == page_id:
              self.view.notebook.set_current_page(page_id)
  
          # set the old colors
          for p in range(number_of_pages):
              page = self.view["notebook"].get_nth_page(p)
              label = self.view["notebook"].get_tab_label(page).get_child().get_children()[0]
              # Gtk TODO
              style = label.get_style_context()