private void BuildUi() { const string menuTemplate = @" <interface> <menu id='app_menu'> <submenu> <attribute name='label'>_File</attribute> <item> <attribute name='label'>_Quit</attribute> <attribute name='action'>app.quit</attribute> <attribute name='accel'><Primary>q</attribute> </item> </submenu> </menu> </interface> "; var menuBuilder = new Builder(); menuBuilder.AddFromString(menuTemplate); var menuModel = new MenuModel(menuBuilder.GetObject("app_menu").Handle); const string windowTitle = "Gtk on Windows"; var headerBar = new HeaderBar { Title = windowTitle, Subtitle = "With GtkSharp", ShowCloseButton = true }; _mainWindow = new MainWindow(this) { Title = windowTitle, IconName = "applications-development", ShowMenubar = false }; if (PrefersAppMenu()) { AppMenu = menuModel; _mainWindow.Titlebar = headerBar; } else { Menubar = menuModel; _mainWindow.ShowMenubar = true; } _mainWindow.ShowAll(); }