static ImageSurface showAudioFileWithEditableMarkers(final File audioFile) {
  L<Float> markers = safeUnstruct(getOneLineFileInfoField(audioFile, 'markers));
  final ImageSurfaceWithXMarkers is = ImageSurfaceWithXMarkers(audioFileToFrequencyImage(audioFile).getBufferedImage(), markers);
  is.onMarkersChanged = r { setOneLineFileInfoField(audioFile, markers := struct(is.markers)) };
  is.setZoom(2);
  showPackedFrame(is);
  ret is;
}