We're using 2010 Vol 3.

If you assign the PopupDragHandleControlID property in a ModalPopupExtender, when the ModalPopupExtender is shown it is obscured by the WebTab, see this screenshot:

Here's the code:

<ig:WebTab ID="WebTab1" runat="server" Width="800px" Height="300px">

<Tabs>

<ig:ContentTabItem Text="<%$ Resources:Dictionary, sGeneral %>" Key="General">

<Template>

<asp:Button ID="B1" runat="server" Text="Show Modal" />

<asp:Panel ID="P1" runat="server" Width="200px" Height="400px" BackColor="Red" BorderColor="Black" BorderWidth="1px">

</asp:Panel>

<act:ModalPopupExtender ID="MPE1" runat="server" TargetControlID="B1" PopupControlID="P1" PopupDragHandleControlID="P1" />

</Template>

</ig:ContentTabItem>

</Tabs>

</ig:WebTab>

Any ideas?