自 OS X 10.11 起，即使使用 setTitle，标题栏似乎也不再出现:有人知道发生了什么以及如何恢复旧行为吗？
最佳答案
来自AppKit Release Notes for OS X v10.11 :
In 10.11, most NSOpenPanels have adopted a design that was formerly reserved only for applications which adopted iCloud Documents support and this panel design was only used if iCloud Drive was turned on in System Preferences. This note will refer to the design as the “iCloud Open Panel Design” although the design is no longer limited to applications with iCloud Documents support.
iCloud 开放面板设计没有任何标题外观，因此它现在似乎已经消失了。我不认为有回头路。
如果您想显示某种消息、描述或标题，您可以使用 message 属性。
关于xcode - NSOpenPanel 中缺少标题栏？，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/36879212/