[gtkmm] resizing vboxes in an hbox

[Tim Flechtner <timf trdlnk com>]

hello everyone,
  sorry for the sort of general question,but. . .

i have a hbox containing several vboxes.  the hbox is set so that its 
children are non-homogeneous, and each child vbox is set to neither fill 
or expand.  i would like the user to be able to set the width of each 
individual vbox to whatever they like, but when i try to do so, the hbox 
re-adjusts itself, and all of the child vboxes resize.  i have tried 
both using size_allocate and set_size_request in the specified child 
vbox, but both approaches lead to the described behavior.  can anyone 
recommend an approach that works for this?

thanks!
-tim