Hi. Maybe someone can implement it? Gtk2 misses it-

   case nCmdShow of
   SW_SHOWNORMAL:
     begin
       if B then
         gtk_widget_show(PGtkWidget(GtkWindow))
       else
       begin
         if not GTK_WIDGET_VISIBLE(PGtkWidget(GtkWindow)) then
           gtk_widget_show(PGtkWidget(GtkWindow));
         gtk_window_deiconify(GtkWindow);
         gtk_window_unmaximize(GtkWindow);
         gtk_window_unfullscreen(GtkWindow);
       end;
     end;
   SW_HIDE:
       gtk_widget_hide(PGtkWidget(GtkWindow));
   SW_MINIMIZE:
     if not B then
       gtk_window_iconify(GtkWindow);
   SW_SHOWMAXIMIZED:
     if B then
       gtk_widget_show(PGtkWidget(GtkWindow))
     else
     begin
       gtk_window_deiconify(GtkWindow);
       gtk_window_unfullscreen(GtkWindow);
       gtk_window_maximize(GtkWindow);
     end;
   SW_SHOWFULLSCREEN:
     if B then
       gtk_widget_show(PGtkWidget(GtkWindow))
     else
       gtk_window_fullscreen(GtkWindow);
   end;