Make_trail doesn't produce a trail

[Avedis Neehus]

Setting make_trail to true doesn't produce the desired result. I tried replicating the problem in a simpler case, but there it works. The code can be found here https://github.com/Avedis-Neehus/3D-EM-Balls/blob/gui/3DEMtest.py where the Ball class should be of interest.

[Bruce Sherwood]

Change "make_Trail" to "make_trail". Effectively your ball object has a "user attribute" make_Trail whose value is True but which does not affect the behavior of VPython.

Bruce