Gold Challenge Segue Exception

Tl;dr: When starting the Gold challenge, a new button with a show segue to a new view controller throws an exception.

After successfully completing the Silver Challenge, I immediately began the Gold.

  1. In ‘Item’ class declaration, changed ‘dateCreated’ to be a variable. (Build / run OK.)
  2. In the ‘DetailViewController’ storyboard interface, added a UIButton to the bottom of the vertical stack view. (Build / run OK.)
  3. Dragged a new UIViewController onto the storyboard. Ctrl-dragged the new button onto that interface to create a ‘Show’ segue. (Build OK, run ERROR.)

The exception highlights the top of the app delegate class declaration. The error message is:

Terminating app due to uncaught exception 'NSInvalidArgumentException', reason: '-[Homepwner.DetailViewController buttonAction:]: unrecognized selector sent to instance 0x7fc78e00aee0'

I can eliminate the problem by giving my new button an empty @IBAction within DetailViewController. But can’t figure out why this should be necessary.

Any ideas? Thanks!

Have you found the answer?