The error text is
Error:this.rowsBuffer[…].idd is null or not an object"
Please advice me.
Are you using static or dynamic mode for xml loading ( dyn. smart rendering or dyn. paging ) ?
The client side sorting can be applied only if all data loaded on client side ( which is not possible in dyn. mode , when data loaded by chunks on demand )
The mentioned error occurs when sorting or filtering applied to the grid in dyn. loading mode with some data not loaded from server side yet.
Also, the issue can be caused by missed or non-unique IDs