Gtk.Window.prototype.set_type_hint

function set_type_hint(hint:Gdk.WindowTypeHint):void {
    // Gjs wrapper for gtk_window_set_type_hint()
}

By setting the type hint for the window, you allow the window manager to decorate and handle the window in a way which is suitable to the function of the window in your application.

This function should be called before the window becomes visible.

Gtk.new_with_buttons and other convenience functions in GTK+ will sometimes call Gtk.Window.prototype.set_type_hint on your behalf.