expanding horizontally but not vertically

["Brian Smith" <dbsoft technologist com>]

	Is it possible to pack widgets into a box that expands horizontally but not 
vertically (or vice versa).  I can stop a widget from expanding by calling 
gtk_widget_set_usize(widget, 0, 20);  to make it expand horizontally but not 
vertically, however the box it's in expands vertically anyway.  Calling 
gtk_widget_set_usize() like that on the box does not stop it from expanding.  Is it 
possible to do this? 

Thanks!

Brian Smith