Using the default xcode template, my SFML app crashes if I try to quit it with the CMD-W shortcut. The problem is that this DOES close the app, but it doesn't return the correct sf::Event. It returns sf::Event::LostFocus instead of sf::Event::Closed.
Since the app only checks for Event::Closed, the app never properly closes. It's obviously easy to check for LostFocus event as well, but that would cause my app to close when a user just deselects the window.