A different approach - subclassing WKWebview, measuring the time between pastes and if they're too close, reject the second attempt.     class WebView: WKWebView {         var previousPasteTimestamp: TimeInterval = .zero         override func paste(_ sender: Any?) {             let currentPasteTimestamp: TimeInterval = Date().timeIntervalSinceReferenceDate             if currentPasteTimestamp - previousPasteTimestamp < 0.2 {                 print("prevent double paste")                 return             }             previousPasteTimestamp = currentPasteTimestamp             super.paste(sender)         }     }