Tkinter custom widget question

[Paul Miller]

I would like to create a widget in Tkinter that has a settable title
and cannot be moved outside of its master widget. What I have in mind
is similar to what happens when you open a new file in say, Excel; the
window containing your application data won't move outside of the main
Excel window. I have no idea how to go about this. :) Any help,
tips, or pointers (except NULL pointers) would be welcome.

Thanks