关于groupbox的问题？

我现在正在做一个groupbox的控件是用复合控件的思想。在上面我用一个label控件，下面再加一个 panel控件组合而成。但是出了问题，label现在老是还在panel上，很难看的。
代码如下：
protected override void Render(HtmlTextWriter writer)
{ // writer.Write (Text);
if(this.Page !=null)
{
this.Page .VerifyRenderingInServerForm (this);
}

this.rendertitle (writer);
//Controls.Add (new LiteralControl ("<br>"));
//writer.WriteBeginTag ("fieldset");
writer.Write (HtmlTextWriter.TagRightChar );
this.renderpanel (writer);
//writer.WriteEndTag ("fieldset");

}
protected virtual void rendertitle(HtmlTextWriter writer)
{
writer.AddAttribute (HtmlTextWriterAttribute.Type ,"Label");
writer.AddAttribute (HtmlTextWriterAttribute.Id ,this.ClientID );
writer.AddAttribute (HtmlTextWriterAttribute.Name ,this.UniqueID );
writer.AddAttribute (HtmlTextWriterAttribute.Value ,this.Text );
writer.AddStyleAttribute (HtmlTextWriterStyle.BorderStyle ,"Outset" );
writer.AddStyleAttribute (HtmlTextWriterStyle.BorderWidth ,"6 px" );
writer.AddStyleAttribute (HtmlTextWriterStyle.Width,this.Text .Length .ToString ()+"1" );
writer.RenderBeginTag (HtmlTextWriterTag.Input );
}
protected virtual void renderpanel(HtmlTextWriter writer)
{
writer.AddAttribute (HtmlTextWriterAttribute.Type ,"Panel");
if (ID!=null)
{
writer.AddAttribute (HtmlTextWriterAttribute.Id ,this.ClientID );
}
writer.AddAttribute (HtmlTextWriterAttribute.Name ,this.UniqueID );
if(this.Width.ToString ()!=null)
{
writer.AddStyleAttribute (HtmlTextWriterStyle.Width,this.Width.ToString () );
}
if(this.Height .ToString ()!=null)
{
writer.AddStyleAttribute (HtmlTextWriterStyle.Height,this.Height.ToString () );
}
writer.RenderBeginTag (HtmlTextWriterTag.Form );
writer.RenderEndTag ();
}

Boolean IPostBackDataHandler.LoadPostData(String postDataKey, System.Collections.Specialized.NameValueCollection postCollection)
{
Text=postCollection[postDataKey];
return false;
}

void IPostBackDataHandler.RaisePostDataChangedEvent()
{

}