Hello,
for my new application, i use this example :
http://samples.infragistics.com/2008.1/webfeaturebrowser/default.htm
[Grid - WebGrid] -> Editing data - Row Updating.

When i wrote only one row and i submit the form, it works fine.
But if i add two rows and i submit the form, i have this error :

[NullReferenceException: Object reference not set to an instance of an object.]
   Infragistics.WebUI.UltraWebGrid.UltraGridRow.GetRowLevel(Boolean thruGroup) +61
   Infragistics.WebUI.UltraWebGrid.UltraGridLayout.System.Web.UI.IStateManager.SaveViewState() +428
   Infragistics.WebUI.UltraWebGrid.UltraWebGrid.SaveViewState() +28
   System.Web.UI.Control.SaveViewStateRecursive() +59
   System.Web.UI.Control.SaveViewStateRecursive() +160
   System.Web.UI.Control.SaveViewStateRecursive() +160
   System.Web.UI.Page.SaveAllState() +466
   System.Web.UI.Page.ProcessRequestMain(Boolean includeStagesBeforeAsyncPoint, Boolean includeStagesAfterAsyncPoint) +1676

On the demo site http://samples.infragistics.com/2008.1/webfeaturebrowser/default.htm, we have the same error.
How can i solve this problem ?

Thanks.
Laurent