title: Get Window handle (IntPtr) from Selenium webdriver's current window GUID
body: <p>I'm trying to capture a screenshot of whole browser screen (e.g. with any toolbars, panels and so on) not only an entire page, so I'm got this code:</p>
  
  <pre><code>using (FirefoxDriver driver = new FirefoxDriver())
  { 
      driver.Navigate().GoToUrl(url);                
  
      ScreenCapture sc = new ScreenCapture();
  
      // How can I find natural IntPtr handle of window here, using GUID-like identifier returning by driver.currentWindowHandle?
      Image img = sc.CaptureWindow(...);
      MemoryStream ms = new MemoryStream();
      img.Save(ms, ImageFormat.Jpeg);
      return new FileStreamResult(ms, "image/jpeg");
  }
  </code></pre>