IDLE 3.0a5 has problems with Unicode

[Sven Siegmund]

Hello,

I am testing Python 3.0a5's handling of unicode strings. Since SPE is
not yet for Python 3.0, I have begun to write in IDLE 3.0a5.

I have a source code which IDLE 3.0a5 cannot parse, but Python 3.0a5
can:

#!/usr/bin/python
# -*- coding: utf-8 -*-

def načtiSlovník(zdroj='slovník.txt'):
    soubor = open(zdroj, mode='r', encoding='utf_8')
    řádky = soubor.readlines()
    for řádek in řádky:
        print(řádek, end='')

načtiSlovník()
# End of source code

I have set up Default Source Encoding to UTF-8 in IDLE's general
configuration. Still, when I open that source code and try to run it,
IDLE complains about "invalid character in identifier" and highlights
"zdroj" red in the first line (sic!).

However, when I run the source code from command line (by "python
<filename>"), it gets executed well and does what it shall do.

I should probably add, that I have installed py3k:62932M, May 9 2008,
16:23:11 [MSC v.1500 32 bit (Intel)] on win32. I use Windows XP SP 3.

Is this a known bug if IDLE 3.0a5 which will be fixed in the final
release?

Greetings,

S.