AjaxControlToolKit HTMLEditorExtender adding anchor tag as a normal text when a link is added

I am unable to write a nice title to this topic because my problem is a little weird. I am using AjaxControlToolkit HTMLEditorExtender in my website to send HTML formatted emails. Every other feature like bold, italic, underline etc. are working fine but when I add a link it shows the HTML code of it as follows:

As you can see BOLD is working but the anchor tag is appearing in HTML code format.

Code for extender and the textbox:

<asp:TextBox ID="TextBox2" runat="server" Height="376px" TextMode="MultiLine" Width="795px"></asp:TextBox> <asp2:HtmlEditorExtender ID="TextBox2_HtmlEditorExtender" runat="server" Enabled="True" TargetControlID="TextBox2"> </asp2:HtmlEditorExtender>

Can any one please tell me why this is happening? Is this some bug with the extender?