If the user makes a typo when setting a custom keybind (in this case "<Alt-Key-up>" instead of "<Alt-Key-Up>") IDLE will silently crash.  From the command-line the error shows as:

Traceback (most recent call last):
  File "C:\Python32\Lib\idlelib\idle.py", line 11, in <module>
    idlelib.PyShell.main()
  File "C:\Python32\Lib\idlelib\PyShell.py", line 1388, in main
    shell = flist.open_shell()
  File "C:\Python32\Lib\idlelib\PyShell.py", line 277, in open_shell
    self.pyshell = PyShell(self)
  File "C:\Python32\Lib\idlelib\PyShell.py", line 856, in __init__
    self.history = self.History(self.text)
  File "C:\Python32\Lib\idlelib\IdleHistory.py", line 12, in __init__
    text.bind("<<history-previous>>", self.history_prev)
  File "C:\Python32\Lib\idlelib\MultiCall.py", line 332, in bind
    self.__binders[triplet[1]].bind(triplet, func)
  File "C:\Python32\Lib\idlelib\MultiCall.py", line 213, in bind
    seq, handler)))
  File "C:\Python32\Lib\tkinter\__init__.py", line 977, in bind
    return self._bind(('bind', self._w), sequence, func, add)
  File "C:\Python32\Lib\tkinter\__init__.py", line 932, in _bind
    self.tk.call(what + (sequence, cmd))
_tkinter.TclError: bad event type or keysym "up"

This is doubly confusing as case sensitivity seems to be applied at random in config-keys.cfg.  

Expected behavior:
Ideally case sensitivity shouldn't matter in config-keys.cfg and if there is an error in the config syntax, that particular line should be ignored and the rest of the file tried.  If IDLE is still able to start, some user friendly error should be displayed indicating the problem line.