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On Windows, IDLE closes all open windows and exits completely, without any error message, when selecting the "Print window" menu command.
Starting IDLE from inside a console, one can see the error message:
Exception in Tkinter callback
Traceback (most recent call last):
 File "D:\apps\python32\lib\tkinter\__init__.py", line 1399, in __call__
 return self.func(*args)
 File "D:\apps\python32\lib\idlelib\IOBinding.py", line 453, in print_window
 command = idleConf.GetOption('main','General','print-command-win')
 File "D:\apps\python32\lib\idlelib\configHandler.py", line 245, in GetOption
 type=type, raw=raw)
 File "D:\apps\python32\lib\idlelib\configHandler.py", line 54, in Get
 return self.get(section, option, raw=raw)
 File "D:\apps\python32\lib\configparser.py", line 789, in get
 d)
 File "D:\apps\python32\lib\configparser.py", line 391, in before_get
 self._interpolate_some(parser, option, L, value, section, defaults, 1)
 File "D:\apps\python32\lib\configparser.py", line 440, in _interpolate_some
 "found: %r" % (rest,))
configparser.InterpolationSyntaxError: '%' must be followed by '%' or '(', found
: '%s'
It is trying to read this entry from the config-main.def file:
[General]
print-command-posix=lpr %s
print-command-win=start /min notepad /p %s
For a ConfigParser file, those %s should be %%s instead. Previous IDLE versions (2.7 and 3.1) read the same entry without problem; I suspect they were using a RawConfigParser or processing the entry in a different way.
As a workaround, replacing %s with %%s in config-main.def is enough, until the code gets fixed.