Because it's by far one of the most annoying issues every developer has with Apple now. It's so frustrating to see the syntax highlighting and auto completion engine crash continuously as you try to figure out what line causes it just so you can rewrite it the more verbose way for the engine not to choke. You may think this has to be a beta version or a newly introduced bug, but no, these issues have been there in the official release for at least 1 1/2 years now. It got better over time, yes, but it's still far from being where it should be.