I should have been more specific.  I meant to run the file directly with python, with IDLE not involved.  "python3 .../path/to/tk_scroll.py".  Howver, running it from an IDLE editor and editing in the resulting non-IDLE text window is almost as good.

This reminds me of when trying to enter a French cedilla crashed tk.  That was fixed about at tk 8.5.15.

The only thing that could be done from IDLE is to add tk(inter) bind calls.