title: Action is executing twice on performClick(nil)
body: <p>I have the problem that my onClick actions are always executed 2 times. I have the following code:</p>
  
  <pre><code>override func awakeFromNib() {
      NotificationCenter.default.addObserver(
          self,
          selector: #selector(self.pressStartbutton),
          name: NSNotification.Name(rawValue: "Startbutton"),
          object: nil)
  }
  
  @objc private func pressStartbutton(notification: NSNotification){
      start_button.isEnabled=true
      start_button.performClick(nil)
  }
  </code></pre>
  
  <p>Each time the "pressStartbutton" function is executed, the action always runs 2 times in a row. How should the code look so that it executes it only once?</p>