Problem changing wxComboBox width

[David Carr]

I'm trying to resize (make more narrow) a wxComboBox.  Calls to SetSize(X,
-1) don't seem affect the width at all.  Is that the right call to change
the width of a wxComboBox?  If it matters, the ComboBox is inside a sizer.
 I'm using wxWidgets 2.8.1 on linux-gtk (Ubuntu Edgy).

Thanks for any help,
David Carr