Double-clicking with the Ruler tool causes a crash

1. Run in debug mode, open a project with an image.
2. Select the Ruler tool.
3. Double-click anywhere on the image. The program crashes with the following log:

Current photo is now Graphosoma1-etac.tif
Traceback (most recent call last):
  File "D:\work\arthropods\arthropoddescriber2repository\arthropod_describer_py\arthropod_describer\common\layer.py", line 119, in mouseReleaseEvent
    layer.mouse_release(event)
  File "D:\work\arthropods\arthropoddescriber2repository\arthropod_describer_py\arthropod_describer\common\visualization_layer.py", line 92, in mouse_release
    self.paint_commands = self.current_tool.viz_left_release(event.pos().toPoint())
  File "D:\work\arthropods\arthropoddescriber2repository\arthropod_describer_py\arthropod_describer\tools\ruler.py", line 132, in viz_left_release
    if pos == self.endpoints[-1]:
IndexError: list index out of range

Process finished with exit code 1

(If two individual clicks are made on the same position instead, nothing strange happens.)