When I write my own UIButton-extended class and make it @IBDesignable, I receive two errors in Interface Builder, namely:
UIButton
@IBDesignable
There are a myriad of problems that can cause this. Fire up Console, and look for the crash report IBDesignablesCocoaTouch...
IBDesignablesCocoaTouch...
I just sorted out a problem with a 3rd party designable which had issues with the valueForKey semantics.
valueForKey