docs: def _handle_double_click(self, event):
          """ Double click with left mouse button focuses the state and toggles the collapse status"""
          if event.get_button()[1] == 1:  # Left mouse button
              path_info = self.view.tree_view.get_path_at_pos(int(event.x), int(event.y))
              if path_info:  # Valid entry was clicked on
                  path = path_info[0]
                  item_iter = self.tree_store.get_iter(path)
  
                  # Toggle collapse status if applicable for this kind of state
                  if self.view.tree_view.row_expanded(path):
                      self.view.tree_view.collapse_row(path)
                  else:
                      if self.tree_store.iter_has_child(item_iter):
                          self.view.tree_view.expand_to_path(path)