Hi Jyoti,
Thanks for the details. The Essential GridGroupingControl is fully compatible with the ASP.NET AJAX Update panel. We have all our samples modified and replaced by the ASP.NET AJAX UpdatePanel. You can check that out our samples (that would use triggers from outside the UpdatePanel),
http://www2.syncfusion.com/samplebrowser/samples.aspx?browseto=Grid.grouping.webAlso, I would want to know if you have registered your trigger control with the ScriptManager. If you still don't get it to work, provide us with a sample. We will modify it and get back to you with the proper solution.
Thanks,
Fahad
ASP.NET Grid TeamSyncfusion Inc.,