Hello,
It can be useful to introduce "allow new vertices" at the Polygon menu: On > you can see all the handles (circles and triangles) Off > only circles.
If you want a line for measure distances, let to introduce points is a problem, or if you want to explain all kind of triangles -for example- you would like to have only circles.
Here it is the cs file.
Regards
etoys-dev@lists.squeakfoundation.org