var win = windowUtils.open(url, {
  name: 'test',
  features: {
    resizable: true,
    width: Math.round(screen.availWidth * 0.6),
    height: Math.round(screen.availHeight * 0.7),
    left: Math.round(screen.availWidth * 0.2),
    top: Math.round(screen.availHeight * 0.15)
  }
});

// this fails
var worker =  workers.Worker({
  window: content
});