Well, I can't believe I just spent over four hours trying to get the Ajax PopupControl working when it contains a DetailsView and Calendar Ajax control in it. Basically, it worked fine in IE7 and Firefox but IE8 and Chrome would kept putting the popup control in the background.

So, then it dawned on me, why not just create my own Ajax Calendar Control. Then, in about 20 minutes I came up with this code. I feel like such an idiot for not doing it before. I am not done the control yet so if you can see ways to improve it then let me know.

Code:
<%@ Control Language="VB" AutoEventWireup="false" CodeFile="CalenderTextBox.ascx.vb" Inherits="Controls_Objects_CalenderTextBox" %>


<asp:UpdatePanel ID="updCal" runat="server">
<ContentTemplate>

<table>
    <tr>
        <td>
            <asp:TextBox ID="txtCalendar" runat="server"></asp:TextBox>
        </td>
        <td>
            <asp:ImageButton ID="btnCal" runat="server" ImageUrl="~/Images/calendar.gif" />
        </td>
        <td>
            <asp:RequiredFieldValidator ID="rfvDate" runat="server" ControlToValidate="txtCalendar"
                Display="Dynamic" ErrorMessage="***"></asp:RequiredFieldValidator>
        </td>
        <td>
            <asp:CompareValidator ID="cvDate" runat="server" ControlToValidate="txtCalendar"
                ErrorMessage="**" Operator="DataTypeCheck" Type="Date"></asp:CompareValidator>
        </td>
    </tr>
</table>           
 <div style="margin-top:-2; text-align:center; position:absolute;">
                <asp:Calendar ID="calPopUp" runat="server" Width="70px" Height="70px" 
                    BackColor="#E6E6D9"  BorderStyle="Outset" BorderWidth="1px"
                    Visible="False"  
                    ForeColor="Black" 
                    NextPrevFormat="ShortMonth" BorderColor="#666633" FirstDayOfWeek="Monday" 
                    Font-Names="arial" >
                    <TitleStyle BackColor="#CDCDB4" ForeColor="Navy" />
                    <SelectedDayStyle BackColor="White" ForeColor="Red" />
                    <TodayDayStyle BackColor="white" ForeColor="Red" />
                </asp:Calendar>
                
</div>

</ContentTemplate>
</asp:UpdatePanel>


Partial Class Controls_Objects_CalenderTextBox
    Inherits System.Web.UI.UserControl
    Public Event Show_Popup()

    Public Property Text() As String
        Get
            Return txtCalendar.Text
        End Get
        Set(ByVal value As String)
            txtCalendar.Text = value

        End Set
    End Property

    Protected Sub btnCal_Click(ByVal sender As Object, ByVal e As System.Web.UI.ImageClickEventArgs) Handles btnCal.Click
        calPopUp.Visible = Not calPopUp.Visible

        If calPopUp.Visible = True Then
            If IsDate(txtCalendar.Text) Then
                calPopUp.SelectedDate = txtCalendar.Text
                calPopUp.VisibleDate = txtCalendar.Text

            End If
        End If
        RaiseEvent Show_Popup()

    End Sub

  

    Protected Sub calPopUp_SelectionChanged(ByVal sender As Object, ByVal e As System.EventArgs) Handles calPopUp.SelectionChanged
        txtCalendar.Text = calPopUp.SelectedDate.ToShortDateString
        calPopUp.Visible = False
        RaiseEvent Show_Popup()

    End Sub

 
    Protected Sub calPopUp_VisibleMonthChanged(ByVal sender As Object, ByVal e As System.Web.UI.WebControls.MonthChangedEventArgs) Handles calPopUp.VisibleMonthChanged
        RaiseEvent Show_Popup()

    End Sub
End Class