[Tkinter-discuss] frame fixed size

[Jeff Epler]

If you want a frame to have a fixed size, regardless of its contents,
then you have to make one of the following method calls:
    f.pack_propagate(False)
or
    f.grid_propagate(False)
depending on whether its contents are positioned with .pack() or with
.grid().

The normal behavior (propagate is True) causes the frame to request a
size that reflects what the children request.  When propagate is false,
the frame uses its width= and height= as the requested size.

Jeff