creating widgets with the same size

[Ionutz Borcoman <borco borco-ei eng hokudai ac jp>]

Hi,

Introduction: I have a frame added to a notebook and a progress bar
which belongs to a status bar. I wont to set the progress bar have the
same dimension with the frame. The dimension of the frame is determined
by the gtk. Both of them should not resize after they are constructed
(they are rightmost controls in the notebook/statusbar). 

Question: Which is the right way to do this ? I try to get the size of
the frame in the show event, but I receive 1 as the width of the frame.
Because of this, the only effect is that the progress bar is shrinked to
width = 1.

TIA,

Ionutz