             // add headding item
             let headdingItem = NSMenuItem()
             headdingItem.title = "<Outline Menu>".localized
-            headdingItem.representedObject = NSRange(location: 0, length: 0)
+            headdingItem.representedObject = NSRange(0..<0)
             menu.addItem(headdingItem)
             
             // add outline items

//  ---------------------------------------------------------------------------
//
//  © 2004-2007 nakamuxu
//  © 2014-2018 1024jp
//
//  Licensed under the Apache License, Version 2.0 (the "License");
//  you may not use this file except in compliance with the License.

    @objc private func invalidateOutlineMenuSelection() {
        
        guard
            let textView = self.textView,
            let popUp = self.outlineMenu, popUp.isEnabled,
            let items = popUp.menu?.items,
            let firstItem = items.first
            else { return }
        
        let location = textView.selectedRange.location
        let selectedItem = items.last { menuItem in
            guard
                menuItem.isEnabled,
