title: TextBox using HTMLEditorExtender does not insert new line when pressing Enter
body: <p>I am using AjaxToolKit's <code>HTMLEditorExtender</code> control in my website. The markup is as follows:</p>
  
  <pre><code>&lt;asp:TextBox ID="TextBox2" runat="server" 
          Font-Names="'lucida grande',tahoma,verdana,arial,sans-serif" Height="100%" OnTextChanged="TextBox2_TextChanged" 
          style="margin-bottom: 26px; font-size: small;" Width="90%"&gt;&lt;/asp:TextBox&gt;
  
  &lt;asp:HtmlEditorExtender ID="TextBox2_HtmlEditorExtender" runat="server" 
          Enabled="True" TargetControlID="TextBox2"&gt;
      &lt;Toolbar&gt;
          &lt;asp:Undo /&gt;
          &lt;asp:Redo /&gt;
          &lt;asp:Bold /&gt;
          &lt;asp:Italic /&gt;
          &lt;asp:Underline /&gt;
          &lt;asp:StrikeThrough /&gt;
          &lt;asp:Subscript /&gt;
          &lt;asp:Superscript /&gt;
          &lt;asp:InsertOrderedList /&gt;
          &lt;asp:InsertUnorderedList /&gt;
          &lt;asp:RemoveFormat /&gt;
          &lt;asp:SelectAll /&gt;
          &lt;asp:UnSelect /&gt;
          &lt;asp:Delete /&gt;
          &lt;asp:Cut /&gt;
          &lt;asp:Copy /&gt;
          &lt;asp:Paste /&gt;
          &lt;asp:Indent /&gt;
          &lt;asp:Outdent /&gt;
          &lt;asp:FontNameSelector /&gt;
      &lt;/Toolbar&gt;
  &lt;/asp:HtmlEditorExtender&gt;
  </code></pre>
  
  <p>Running the application, and pressing <em>Enter</em> while <code>TextBox2</code> has focus, no new line is inserted; <strong>instead, <code>TextBox2</code> loses focus</strong>.</p>
  
  <p>This doesn't happen <strong>unless</strong> the <code>HTMLEditorExtender</code> is attached to <code>TextBox2</code>.</p>
  
  <p><strong>More Details</strong></p>
  
  <p>I am running the application in local IIS. The website is live but the feature is not launched on the main website yet. I am using ASP.NET WebForms and latest AjaxToolkit version. Also this problem is in every browser including Chrome, IE, Opera, Firefox.</p>