Tkinter button doesn't appear in OS X

[crystalattice]

Kevin Walzer wrote:
>
> What version of Tk are you running? I've seen this bug on old versions
> of Tk (i.e. 8.4.7) but not recently.
>
> --
> Kevin Walzer
> Code by Kevin
> http://www.codebykevin.com

I'm using Python 2.4.2, which I believe is the default version for OS
X.  How do I check the Tk version?  Can I force my programs to use a
different version of Python, e.g. if I installed Python 2.5?