Gtk.ApplicationWindow:show-menubar

"show-menubar"             Boolean                : Read / Write / Construct

If this property is true, the window will display a menubar that includes the app menu and menubar, unless these are shown by the desktop shell. See Gtk.Application.prototype.set_app_menu and Gtk.Application.prototype.set_menubar.

If false, the window will not display a menubar, regardless of whether the desktop shell is showing the menus or not.