title: Corner radius not showing on button in storyboard with @IBDesigable/@IBInspectable
body: <p>I have this custom class for a button.</p>
  
  <pre><code>import UIKit
  
  @IBDesignable
  class CustomButton: UIButton {
  
      @IBInspectable var cornerRadiusValue: CGFloat = 10.0 {
          didSet {
              setUpView()
          }
      }
  
      required init?(coder aDecoder: NSCoder) {
          super.init(coder: aDecoder)
          self.layer.cornerRadius = 10.0
      }
  
      override func awakeFromNib() {
          setUpView()
      }
  
      override func prepareForInterfaceBuilder() {
          super.prepareForInterfaceBuilder()
          setUpView()
      }
  
      func setUpView() {
          self.layer.cornerRadius = 10.0
      }
  
  }
  </code></pre>
  
  <p>But the corner radius is not showing on the button in the storyboard. </p>
  
  <p>I understand @IBInspectable just allows you to change the value in the inspector panel. I guess thats not what I am looking for. </p>
  
  <p>I would like the corner radius to just show in storyboard when I create a button with that class. Which I thought that's what @IBDesignable does.</p>