I noticed there's a new FormGroup property on Ext:Panel that looks very slick. It works great if set in ASPX but not when set in code behind. Here's a sample page to reproduce:

ASPX body
<body>
<script runat="server">
    Protected Sub Page_Load(ByVal sender As Object, ByVal e As System.EventArgs) Handles Me.Load
        Dim newAnchor As New Anchor
        Dim pnl As New Coolite.Ext.Web.Panel
        pnl.FormGroup = True
        pnl.Title = "Panel2"

        Dim text As New LiteralControl("Body2")
        pnl.BodyControls.Add(text)

        newAnchor.Items.Add(pnl)

        Me.pnlForm.Anchors.Add(newAnchor)
    End Sub
</script>

    <form id="form1" runat="server">       
    <ext:ScriptManager ID="ScriptManager1" runat="server">
    </ext:ScriptManager>
    <ext:ViewPort runat="server">
        <Body>
            <ext:FitLayout runat="server">
                <ext:Panel runat="server">
                    <Body>
                        <ext:FormLayout ID="pnlForm" runat="server">
                            <ext:Anchor>
                                <ext:Panel runat="server" FormGroup="true" Title="Panel1">
                                    <Body>
                                        Body1
                                    </Body>
                                </ext:Panel>
                            </ext:Anchor>
                        </ext:FormLayout>
                    </Body>
                </ext:Panel>
            </ext:FitLayout>
        </Body>
    </ext:ViewPort>
    </form>
</body>