How to hide the menu on a title bar?

["Kang, Michael" <MKang sweda com>]

Hi,

It is a question about decorations.
I am writing a application with gtk on Linux 9. My application needs a
border and a title bar without closing, minimizing, maximizing and menu
buttons.
I've been successful on hiding the closing, minimizing and maximizing button
by using following code:
   gtk_widget_realize (window);
   gdk_window_set_decorations (window->window,
                (GdkWMDecoration)(GDK_DECOR_BORDER|GDK_DECOR_TITLE ));
   gdk_window_set_functions (window->window,
                (GdkWMFunction)(0));
   gtk_widget_show (window);
But the menu button(on the very left of title bar) is still there.

Does the window manager allow to hide it?
If so, what am I supposed to do?

thanks,
Michael