show/hide widget within other widget

[Andreas Kotowicz <kotoml mynetix de>]

I have a main.c file like this:

int main(int argc, char **argv)
{
  GnomeProgram *program;

  program = gnome_program_init(bla, bla, ..)
  create_mainwindow();
  gtk_main();
  return 0; 
}

where create_mainwindow reads like following:

void create_mainwindow (void)
{
  GnomeApp *window;
  window = create_ui();
  GtkWidget *calendar;
  calendar = create_calendar();
  gnome_app_set_contents(window, GTK_WIDGET(calendar));
 
  gtk_widget_show_all(GTK_WIDGET(window));
}

as you may guess, create_ui just sets up the window with menu and tool
bars, etc. 
create_calendar creates a gtkcalendar.

Now in my create_ui function I have a menu option for enabling/disabling
the calendar. as the calendar is enabled by default, how should I now
disable (maybe hide) it? what's the most elegant solution for this
problem? I also think about the possibility to choose from a variety of
widgets to be displayed inside the contents window. and in my eyes it
doesn't make sense to first create all those widgets and then manually
show/hide them as needed (suppose I just want to have one widget at a
time).

I'm welcome for any suggestions,
cheers,
Andreas