resizing widgets in a toolbar

[adrian <feiguin ifir ifir edu ar>]

I'd like to resize a combo widget inside a toolbar. I realized that the
toolbar allocation routine fixes the child widget size to the child
requested size. I've been playing arround with widget_set_usize but I
couldn't get the desired results. Your help could do the things easier to
me. Thank you for any hint,
<ADRIAN>