[Solved] ASP.Net DropDownList showing behind AJAX ModalPopupExtender Modal Popup

Hi,

In Rad grid Control, Drop down List control is geting hidden in the Modal Popup. When i Click the Drop down list its open in the back side of the Modal Pop up.

Actually my dropdown list is displaying in the backside of the Modal Popup. I am unable to select and see the list of items.

Any other way to bring the list infront of modal popup window?

<cc1:ModalPopupExtender ID="MdlPopUp" runat="server" PopupControlID="pnlpopup" TargetControlID="HiddenTargetShow"
    BackgroundCssClass="modalPopUpBackground" OkControlID="btnspeccompclose">
</cc1:ModalPopupExtender>
<asp:Panel ID="pnlpopup" runat="server" HorizontalAlign="Center" BorderColor="#0093C2"
    BackColor="#ffffff" BorderWidth="2px" CssClass="myPanelClass" ScrollBars="Auto" Width="525px">
    <asp:UpdatePanel ID="UpdatePanel2" runat="server">
    <tr>
        <td>
            <telerik:RadComboBox ID="txtCOL" runat="server" Skin="Outlook" CssClass="dropdown-view" Width="200px" TabIndex="55" ZIndex="12000">
                <CollapseAnimation Duration="200" Type="OutQuint" />
            </telerik:RadComboBox>
        </td>
    </tr>