I'd like to create a rich textbox which inherits from TextBox:

   public class MyTextBox : TextBox
   {
       protected override void Render(HtmlTextWriter writer)
       {
           base.Render(writer);
           LinkButton button = new LinkButton();
           button.Text = "Button";
           button.RenderControl(writer);
       }
   }

But in the output produced the linkbutton is no longer a LinkButton
but just plain text. If i inherit from CompositeControl everything
woks find but then my testbox is no longer a TextBox.

Is there a way to make my linkbutton work and my textbox remains a
TextBox?