I really struggled with the first challenge, but the second challenge was straightforward.
I added the following to MainWindowControler.swift
override func validateMenuItem(menuItem: NSMenuItem) -> Bool {
if window!.firstResponder is DieView {
return true
}
else {
return false
}
}
Then added a dummy text-field to the MainWindowController.xib so I could take window.FirstResponder away from the dice (just for test purposes).