Painting order in gtk2 vs gtk1.2

[Pierre Habraken <Pierre Habraken imag fr>]

Hello,

I am a newbie to gtk based app. development.
I am a teacher and have to migrate an educational program from gtk1.2 to 
gtk2.

The main window of this program contains a background image with several 
buttons for triggering miscellaneous actions.
These buttons must reside at fixed locations. So, everything displayed 
in the main window is contained in a GtkFixed widget, which one belongs 
to the main window.

I am faced to the following issue:
- with gtk1.2, everything works fine.
- with gtk2, buttons are hidden "behind" the background image: they are
  not visible but if one click at the location where a button resides,
  the corresponding action is triggered.

My question is thus: how to force buttons to be painted after the 
background image has been painted ?

I join a small program which behaves as explained above.
When compiled with options CFLAGS=-Wall -Werror `gtk-config --cflags` 
and LDFLAGS=`gtk-config --libs` the button is displayed upon the 
background image.
When compiled with options CFLAGS=-Wall -Werror `pkg-config --cflags 
gtk+-2.0` and LDFLAGS=`pkg-config --libs gtk+-2.0` the button is hidden 
(though it reacts if one click to the right place).

Thanks a lot in advance for any help.

Pierre
--
Pierre HABRAKEN - mailto:Pierre Habraken imag fr
Tél: 04 76 63 59 94 - Fax: 04 76 51 47 93