Scaling in one direction

[Lachlan Gunn <lachlan76 gmail com>]

Hi,
I'm making an application that has a vbox that I want to only resize
horizontally (ie. when I extend the window horizontally, it becomes
wider, but when I extend vertically it stays the same size).  I
haven't been able to figure this out, is there anyone here who could
help me?
--
Thanks,
Lachlan