Calls to the widget method tk_focusNext() fail with
"unsubscriptable object" error. Looking at the Tkinter.py 
code for the routine shows this statement:

name = self.tk.call('tk_focusNext', self._w)

(line 433)

which used to return a string in 2.2 but now returns
a "cmdName object". When this is passed to 
self._nametowidget(name), it fails when it tries to
subscript name (line 1006) since the object does
not support indexing. Perhaps str(name) or
name.string is more appropriate now? (when
that change is made, it works--well, I tested
name.string and that worked)

Perry Greenfield (perry@stsci.edu)