         // render the waveform
         waveformView.audioURL = sting.url
         
-        NotificationCenter.default.addObserver(self, selector: #selector(updatePreviewButtonPositions), name: .waveformViewDidUpdate, object: nil)
+        NotificationCenter.default.addObserver(self, selector: #selector(layoutWaveformOverlayViews), name: .waveformViewDidUpdate, object: nil)
         
         startMarkerView.dragRecogniser.addTarget(self, action: #selector(startMarkerDragged(_:)))
         endMarkerView.dragRecogniser.addTarget(self, action: #selector(endMarkerDragged(_:)))

        endPlayButton.isEnabled = previewLengthControl.selectedSegmentIndex > 0
    }
    
    @objc func updatePreviewButtonPositions() {
        if let startSample = waveformView.highlightedSamples?.lowerBound, let x = waveformView.position(of: startSample) {
            startPlayButtonHorizontalLayoutConstraint.constant = waveformView.position(of: startSample) ?? 0
            startMarkerHorizontalLayoutConstraint.constant = x

        NotificationCenter.default.post(name: .didFinishEditing, object: sting)
    }
    
    override func viewDidLayoutSubviews() {
        layoutWaveformOverlayViews()
    }
    
    func updateLabels() {
        navigationItem.title = sting.name ?? sting.songTitle
        titleLabel.text = sting.songTitle
