I have a basic modal popup that is not working correctly in Firefox 23.0.1. The popup randomly flickers at the top of the page during post backs when the OK button is clicked but works as intended when the cancel button is clicked. This issue does not exist in IE10.
Thanks
<%@ Page Language="VB" AutoEventWireup="false" CodeFile="Default.aspx.vb" Inherits="_Default" %><!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"><html xmlns="http://www.w3.org/1999/xhtml"><head runat="server"><title></title></head><body><form id="form1" runat="server"><asp:ToolkitScriptManager ID="ToolkitScriptManager1" runat="server"></asp:ToolkitScriptManager><asp:Button ID="btnShow" runat="server" Text="Show" /><asp:ModalPopupExtender ID="mpeDelete" runat="server" DynamicServicePath="" PopupControlID="pnlDelete"
TargetControlID="btnShow" BehaviorID="modal_popup" CancelControlID="btnCancel"
BackgroundCssClass="modal_background" DropShadow="true" Enabled="True"></asp:ModalPopupExtender><asp:Panel ID="pnlDelete" runat="server" CssClass="modal_popup" Style="display: none"><asp:Button ID="btnCancel" runat="server" Text="Cancel" /><asp:Button ID="btnOK" runat="server" Text="OK" /></asp:Panel></form></body></html>