I'm trying to underline a UIBarButtonItem, but the following has no effect:
testBarItem.setTitleTextAttributes([
NSUnderlineStyleAttributeName:NSUnderlineStyle.StyleDouble.rawValue
], forState: .Normal)
Changing other properties such as NSForegroundColorAttributeName does work.
The same code above used with an NSAttributedString and a UILabel does underline the text, so why does this not work with a UIBarButtonItem?