I verified problem continuing problem windows. There is only a 'crash' when running under pythonw, which does not happenon linux, as far as I know. When running on a console, the error traceback is the same as in msg145581 (with line numbers altered). Changing some ValueError to a TclError did not affect either UnicodeDecodeError or the problem of error reports crashing Idle because there is no stderr to send them to.

This type of crash is a generic problem addressed by #13582. The solution to that would solve the crash part of this issue, but not the message. I would like to see the 2.x message, possibly improved. Perhaps we should resurrect the 2.x codec for processing text pasted into the shell.

As for text windows,
# -*- coding: utf-8 -*-
print('𐒢')
# ðﾐﾒﾢ
which is not good either.