Window sizes

[Chad Nicolas Tindel <ctindel lug ee calpoly edu>]

I'm having a little trouble controlling the properties of the windows that
I create.  What I'm trying to do is have one main window (a gtk_vbox), and
have everything pack into that.  This then will be added to the
container returned from gnome_app_new.  I'd like to be able to set the
this of this main window, and have it stay the same, as well as centered
in the Application window.  The problem is, the vbox keeps resizing itself
to expand/fill the window, instead of staying the same size.  

So my question is, how do you change a window's properties so that it does
not expand/fill?  I know how to tell a table not to let it's contents
expand, but changing a windows properties so that it doesn't expand itself
doesn't seem clear to me.

Any help you can give would be very appreciated.

Thanks!

Chad