Gtk.Menu.prototype.set_tearoff_state

function set_tearoff_state(torn_off:Boolean):void {
    // Gjs wrapper for gtk_menu_set_tearoff_state()
}

Changes the tearoff state of the menu. A menu is normally displayed as drop down menu which persists as long as the menu is active. It can also be displayed as a tearoff menu which persists until it is closed or reattached.