matplotlib interactive windows hang

I am testing matplotlib for the first time, but it

    > continuously hang after a really short time.

    > I read all the troubles about running it from an ide, so
    > i'm using plain cmd.


    > The Python prompt is still functional. When i try to exit
    > i get (WXAgg backend):

Even in plain command mode "shell", you need a special shell to work
interactively, or you need to use TkAgg. WX* and GTK* both require
special shells to work interactively. It looks from your post that
you are trying to use wxagg from the standard python shell. This is
known not to work. If you want wx + interactive shell, try pycrust.
This is discussed on

Your best bet for interactive use on win32 is TkAgg.

You should try setting in C:\Python23\share\matplotlib\.matplotlibrc

backend : TkAgg
interactive : True

and try using either the standard python shell or ipython. If that
works, you should look at the additional setting in your rc file

tk.window_focus : True # Maintain shell focus for TkAgg

Hope this helps,
John Hunter