I was able to reproduce the bug. @anon42388993, once that window is open you have to first go to Options -> Configure and then watch your terminal. @piusbnsl, I think that error comes from an incompatible version of the Tcl/Tk package. I'm not sure how to fix it.
Under Ubuntu MATE 16.04:
tcl is already the newest version (8.6.0+9).
Edit: idle3 is also affected.
Edit2: Submitted bug report on launchpad: Bug #1598673, please mark yourselves as affected using the green link at the top of the page so the bug report will be confirmed and people can start working on it.