A bug from Tkinter is present in the current release.

https://sourceforge.net/tracker/index.php?func=detail&aid=2643483&group_id=5649&atid=105649

8tixFileEntry:OpenFile dialogtype tk_chooseDirectory only opens once.

There is a bug fix in the code.  I tried it in my copy and it does fix the problem.  Perhaps it can be propagated in Python 3 releases.  Or push for tkinter to update their copy.

I think you are confusing the Tix widget set, an independent Tk-based project, with Tkinter, the Python interface to Tk, which is part of Python.  The problem you linked to appears to be a Tix issue.  That code is not part of Python.  It needs to be addressed by the Tix project.

Ah, I see now that the question is actually about the python.org Windows installers which, as a service to the user, pull in the external source of Tix during the build.  (Tix is not included in the Python source distribution nor with the Mac OS X installers.)  Martin, any interest in adding a Tix patch to the installer build?

Gary, did you mean that there is a fix in the Tix bug report?
(the addition of '-'?)
If so, what has it not been applied to the Tix repository?
Is it still active?
Once changed there, the change should be propagated to the Python distribution.

Terry, I am just a new casual user.

The fix described in the Tix report (adding the '-') fixed the problem for me.  But the report (2009-02-26) is after the most recent Tix build (8.4.3	2008-03-17).  I don't know if it was ever added to the repository.   

Is Tix still being supported?  No, the last CVS change was FileEnt.tcl revision 1.7 by hobbs, Sun Mar 28 02:44:57 2004.  Looks pretty dead to me.

If not, a good reason for me to skip Tix and use tkinter and ttk.  There have been recent commits (last commit on 2011-06-30).

I do not think there is any pydev interest in separately patching tix, any more than we patch tk itself.