Another Strange Behavior in VS Design Mode

Do you see any thing wrong with the following code?

I want to create a Button1_Click event for Button1 but the property page is grayed out in design mode. I manually created the event but clicking on button won't execute this code. I am trying to refresh a GridView on parent page from AJAX Popup is closed.

protected void Button1_Click(object sender, EventArgs e)
{
   ProcessMyRequest();
}

<asp:ModalPopupExtender ID="ModalPopupExtender1" runat="server" PopupControlID="Panl1" TargetControlID="lnkProcess"
                    BackgroundCssClass="Background"></asp:ModalPopupExtender><asp:Panel ID="Panel10" runat="server" CssClass="Popup" align="center" style = "display:none"><iframe style=" width: 500px; background-color:lightsteelblue; height: 400px;" id="Iframe2" runat="server"></iframe><script>
                (function () {
                    var pageurl = "WebForm1.aspx?Module=Mod1";
                    var txtCourseValue = document.getElementById("txtCourse").value;
                    if (txtCourseValue != undefined) {
                        document.getElementById("Iframe1").src = pageurl + "&Page=" + txtCourseValue;
                    }
                })();</script>           <br/><asp:Button ID="Button1" runat="server" Text="Close" CausesValidation="False"/></asp:Panel>