Problems with Tkinter and maximized/fullscreen mode

I wrote my first Python Tkinter program, CaltrainPy. It is a Caltrain
schedule program. It is a bit
slow, and butt-ugly, but beats the competition in the UI functionality I
think. http://www.heikkitoivonen.net/blog/?p=11

I would like the window to be maximized, but all my attempts so far just
lead to a case where the window is maximized but the all the controls
still huddle in the middle. Also, when I do this, the OptionMenu control
starts misbehaving - clicking on it will close it immediately and to
actually use it you have to press and hold mouse button 1, scroll to the
entry you want, and then release the mouse button. Any ideas?

I am sure it has lots of other warts, being my first Tkinter program and
all, so all comments about the code would be appreciated.

-- 
  Heikki Toivonen