Vlastimil: you are mixing issues. Some of your observations are actually correct behaviour; please don't clutter the report with that, but report each separate behavior in a separate report. In Python 3.3, surrogate pairs do *not* substitute for the the actual character, since the internal representation is not UTF-16 anymore.

Also, when you run a Tkinter app in IDLE: while you get a "proper" traceback output, your conclusion that python.exe does not "crash" is incorrect: it crashes just in the very same way that IDLE crashes. Except when run inside IDLE, it is a subprocess that "crashes" (i.e. terminates with a traceback output), not IDLE itself.