xcode 6 interface builder very slow performance when showing viewcontrollers with constraints

Question

I have an problem with Xcode 6 really responding very slowly to user interactions, e.g. editing code, scrolling areas etc. This particularly happens when the interface builder s

Answer 1

I had this same problem where performance plummeted on an external display.

What I ended up discovering was that the external monitor issue was indicating that there was a UIView that interface builder couldn't quite figure out properly for auto-layout.

In my case it was a UIToolbarBarItem that contained a UIView that contained a UILabel. Once I removed the offending UIToolbarBarItem the performance issue resolved itself. It went from being completely unusable to smooth scrolling.

You should check if you have a UIView inside something that might cause auto-layout to freak out.