Controlling resizing of boxes when a window is resized

["Ian Puleston" <ian underpressuredivers com>]

Hi,

I have an app that has its main display divided vertically into two - an
upper box displaying various things, and a lower box containing buttons. I
use a gtk_widget_set_size_request to set the minimum size of the upper box,
and let the lower button box choose its own size.

The problem is if the user resizes the window, it is the height of the lower
button box that gets resized while the upper box stays unchanged, which is
exactly the opposite of what I want.

So, is there some way to control which child boxes within a window get
resized when the window is resized?

Ian