AJAX :: Modal Popup Closes On Background Click?

I have a modal popup that on the first time it is running, if the user clicks the greyed out background the modal closes. On the 2nd and later times it runs correctly. The user can click the background and it works correctly. I have searched around and tried a few things with out any luck.

Here is the code.

<telerik:RadScriptManager ID="RadScriptManager1" runat="server" EnablePageMethods="true" EnablePartialRendering="true"> </telerik:RadScriptManager>
<ajax:ModalPopupExtender ID="GlobalModalPopupExtender" runat="server" PopupControlID="GlobalpnlPopup" TargetControlID="GlobalMain" BackgroundCssClass="modal_background"> </ajax:ModalPopupExtender>
<div id="GlobalMain" runat="server"> </div> <asp:Panel ID="GlobalpnlPopup" runat="server" Style="display: none; background-color: White; border-width: 4px; border-style: solid; border-color: #EA0A8D; padding: 4px; height: 40px; width:
200px; z-index: 10000; " CssClass="RadButton"> <table align="center"> <tr> <td align="center"> <asp:Image ID="imgGlobalProcessing" CssClass="progress_image" runat="server" ImageUrl="~/images/ajax-loader.gif"
/> <b>Processing...</b> </td> </tr> </table> </asp:Panel>
<script type="text/javascript">
Sys.Application.add_load(GlobalApplicationLoadHandler);
function GlobalApplicationLoadHandler(sender, args) { var prm = Sys.WebForms.PageRequestManager.getInstance(); if (!prm.get_isInAsyncPostBack()) { prm.add_initializeRequest(initRequest); prm.add_endRequest(endRequest);
} } function timer() { return true; }
function initRequest(sender, args) { var pop = $find("<%=GlobalModalPopupExtender.ClientID%>"); pop.show(); }
function endRequest(sender, args) { var pop = $find("<%=GlobalModalPopupExtender.ClientID%>"); pop.hide(); } </script>
.modal_background { background-color:Gray; filter:alpha(opacity=65); -moz-opacity:0.65; /* It is for Mozilla firefox browser */ Opacity:0.65; }