Shrinking entry boxes?

["James K. Wiggs" <wiggs novum-millennium org>]

 Good day, Folks;

   I'm busy building input GUIs for an application I'm working on,
and I'm using a lot of GtkComboBox widgets for text and numerical
inputs.  I've been building the base code using Glade and then
modifying it to use some of my internal functions to create/edit
the contents of the combolists.  My question is this: how do I
force these boxes to shrink down to a reasonable size?  Even if I
set the parameters in Glade for expand and fill to false, they
end up being anywhere from 2 to 5 times as large as they need to
be for the input values they contain.  A combo box with an input
list whose longest value is perhaps 6-7 characters will end up
large enough to hold over 20 characters.  Combo boxes that contain
only integer values ranging up to 200 or so will *still* be about
20 characters wide, even though only 3-4 are needed.  Is there
some way to manually force these things to only be N characters or
perhaps N pixels wide?  Or does GTK+'s internal size allocations
code preclude this, short of using a Layout widget?

   Many thanks for any suggestions.

best,
Jim Wiggs
wiggs wiggs org