title: GeckoFx-14 PromptService is not working
body: <p>I was testing the GeckoFxTest project which was given with main geckofx source file. But when I was testing the customPrompt for private proxies, unfortunately its not working. I uncommented these lines :</p>
  
  <pre><code>GeckoWebBrowser.UseCustomPrompt();
  
  GeckoPreferences.User["browser.xul.error_pages.enabled"] = false;
  </code></pre>
  
  <p>and for private proxy I used these codes :</p>
  
  <p><code>
  Gecko.GeckoPreferences.User["network.proxy.http"] = host; Gecko.GeckoPreferences.User["network.proxy.http_port"] = port; Gecko.GeckoPreferences.User["network.proxy.ssl"] = host; Gecko.GeckoPreferences.User["network.proxy.ssl_port"] = port; Gecko.GeckoPreferences.User["network.proxy.type"] = 1;
  </code></p>
  
  <p>Without <code>GeckoWebBrowser.UseCustomPrompt()</code> it is prompting for username and password, but after uncommenting it - its keep showing "Access to requested resource disallowed by administrator or you need valid username/password to use this resource". Am I missing anything ?</p>
  
  <p>Thanks</p>