title: "DropDownList.SelectedIndex = -1" problem
body: <p>I just want an ASP.NET DropDownList with no selected item. Setting SelectedIndex to -1 is of no avail, so far. I am using Framework 3.5 with AJAX, i.e. this DropDownList is within an UpdatePanel.
  Here is what I am doing:</p>
  
  <pre><code>    protected void Page_Load (object sender, EventArgs e)
      {
          this.myDropDownList.SelectedIndex = -1;
          this.myDropDownList.ClearSelection();
  
          this.myDropDownList.Items.Add("Item1");
          this.myDropDownList.Items.Add("Item2");
      }
  </code></pre>
  
  <p>The moment I add an element in the DropDown, its SelectedIndex changes to 0 and can be no more set to -1 (I tried calling SelectedIndex after adding items as well)... What I am doing wrong? Ant help would be appreciated!</p>