Section Header
    + name := G_RAW;
    - author := "Sonntag Benoit (bsonntag@loria.fr)";
    - comment := "Group elements for GUI.";
Section Inherit
    + parent_g_group:Expanded G_GROUP;
Section Public
Size.
    - width_min:INTEGER <-
    - height_min:INTEGER <-
Update position.
    - set_position rac:AREA at (x,y:INTEGER) size (w,h:INTEGER) <-
Display.
    - draw_slave bmp:ABSTRACT_BITMAP from (x0,y0:INTEGER) to (x1,y1:INTEGER) <-
    - draw (x0,y0:INTEGER) to (x1,y1:INTEGER) <-
Event manager.
    - receive msg:EVENT <-