docs: def current_pointing(self, index):
          """set the color of the currently selected pointing to 'blue'"""
          if self.current is not None:
              for item in self.pointings[self.current]['items']:
                  self.itemconfigure(item, outline="black")
          self.current = index
          for item in self.pointings[self.current]['items']:
              self.itemconfigure(item, outline="blue")