NSTextAttachment 图像未显示在 NSTextView 中（但显示在 UITextView 中）？

我在获取时遇到问题NSTextAttachment工作图像NSTextView对于 OS X 应用程序。

的形象NSTextAttachment只是根本不显示。然而，它似乎仍然设置正确。因为在复制内容的时候NSTextView并将其粘贴回例如TextEdit.app，粘贴的文本正确包含图像。

这是一个重现该问题的最小游乐场：

import Cocoa

let img = NSImage(named: "Checked")

let textView = NSTextView(frame: NSMakeRect(0, 0, 254, 64))

let attrstr = NSMutableAttributedString(string: "Test")

let attch = NSTextAttachment()
attch.image = img

attrstr.appendAttributedString(NSAttributedString(attachment: attch))

textView.textStorage!.setAttributedString(attrstr)

textView

预期输出：

对于 iOS，因此使用 UIKit 而不是 Cocoa，它工作得很好：

import UIKit

let img = UIImage(named: "Checked")

let textView = UITextView(frame: CGRectMake(0.0, 0.0, 200.0, 44.0))

let attrstr = NSMutableAttributedString(string: "Test")

let attch = NSTextAttachment()
attch.image = img

attrstr.appendAttributedString(NSAttributedString(attachment: attch))

textView.attributedText = attrstr

textView

我使用的是XCode 7。两个playground都可以下载here https://dl.dropboxusercontent.com/u/6699613/nstextattachmentplayground.zip.

非常欢迎任何想法，提前致谢！

var thumbnailImage: NSImage? = // some image
var attachmentCell: NSTextAttachmentCell = NSTextAttachmentCell.initImageCell(thumbnailImage!)
var attachment: NSTextAttachment = NSTextAttachment()
attachment.attachmentCell = attachmentCell
var attrString: NSAttributedString = NSAttributedString.attributedStringWithAttachment(attachment)
self.textView.textStorage().appendAttributedString(attrString)