The popup itself pops up fine and I've used this method before to use this control.
The difference this time is that I want to pre-populate the popup from my main form.
So in my Panel that makes up the popup I might have a label and from my main form (another panel on the same page) I set the value of this label. However when I come to display the panel, the value of the label has been lost.
So to help clarify I have the following Declared:
The Function showRelationShipPopup is called from a button on the main panel, This initiates the popup.
<cc1:ModalPopupExtender ID="mpeModifyRelationships" runat="server" PopupControlID="ModifyRelationships" TargetControlID="btnFake" BackgroundCssClass="modalBackground" CancelControlID="RelationshipCancelButton" >
$get('<%=ModifyRelationships.ClientID %>').className = "modalpopup";
<asp:Panel ID="ModifyRelationships" runat="server" Height="500px" Width="1000px" BackColor="White" BorderStyle="Solid" CssClass="hidden" ScrollBars="Auto">
<td>Attribute: <asp:Label ID="lblAttribute" runat="server" Text=""></asp:Label></td>