title: ConfigureAwait(false) still deadlocks
body: <p>I've been reading up a bit on <code>async/await</code> and was trying to reproduce a deadlock scenario in windows forms by calling <code>WebClient.DownloadStringTaskAsync</code> on the UI thread and then calling <code>task.Result</code> on the UI thread while the task was executing. This resulted in a deadlock. </p>
  
  <p>Then I tried to address the issue by calling <code>ConfigureAwait(false)</code> on the returned task, but to my surprise that still caused a deadlock. My understanding is that it should execute the continuation of the method on a different thread and hence there should be no deadlock. What am I missing?</p>
  
  <p>I know how to get around the issue but thought <code>ConfigureAwait(false)</code> would fix it as well.</p>
  
  <p>Here is the code, I am using NET 4.5</p>
  
  <pre><code>    private async void button1_Click(object sender, EventArgs e)
      {
          // Deadlocks!
          Task&lt;string&gt; task = DownloadAsync();
          textBox1.Text = task.Result;
  
          // Works
          //textBox1.Text = await DownloadAsync();
      }
  
      private static async Task&lt;string&gt; DownloadAsync()
      {
          var client = new WebClient();
  
          string result = await client.DownloadStringTaskAsync("http://www.rpmglobal.com").ConfigureAwait(false);          
  
          return result;
      }
  </code></pre>