I created a test page based on your information. The page contains a WebGrid (bind to Customers table of Northwind.mdb database) with GroupedColumns (grouped by ‘Country’ field) and ClassicPaging enabled. The grid should be able to restore the expanded grouped rows after moving to a page.

First, a global variable in client-side script is created in order to keep the information of the expanded grouped row state and the corresponding page. The value of the global variable will be modified on OnGroupExpand and OnGroupCollapse of WebGrid client side event. And finally in OnAfterResponseProcess, the expanded grouped rows of current page are restored.

I enclosed my test page as attachment. Please have the attached files tested on your end and let us know whether it suits to your scenario or not.