I am using Xceed Datagrid on a Silverlight Navigation Page and I get the below unhandled exception when I navigate into the page from 2nd time onwards. The very first time I navigate into this page everything works fine but throws the following exception 2nd time onwards. This keeps throwing the same exception everytime I navigate into this page. The only option available after I get this exception is to refresh the browser (which reloads the silverlight application) at which time It starts working fine but only the first time around.

Unable to cast object of type 'MS.Internal.ManagedObjectReference' to type 'Xceed.Silverlight.DataGrid.DataGridGroupConfigurationSelector'.

   at Xceed.Silverlight.DataGrid.DataGridControl.get_GroupConfigurationSelector()

Here's the codes snippet where the exception occurs in DataGridControl.cs

 public DataGridGroupConfigurationSelector GroupConfigurationSelector
    {
      get
      {
        return ( DataGridGroupConfigurationSelector )this.GetValue( DataGridControl.GroupConfigurationSelectorProperty );
      }
      set
      {
        this.SetValue( DataGridControl.GroupConfigurationSelectorProperty, value );
      }
    }

[update]

Here's the entire Stack trace

Unable to cast object of type 'MS.Internal.ManagedObjectReference' to type 'Xceed.Silverlight.DataGrid.DataGridGroupConfigurationSelector'.

   at Xceed.Silverlight.DataGrid.DataGridControl.get_GroupConfigurationSelector()
   at Xceed.Silverlight.DataGrid.DataGridControl.OnQueryDataGridConfiguration(Int32 index, DataPath dataPath)
   at Xceed.Silverlight.DataGrid.DataGridControl.GroupHeaderFooterConfigurationAdapter.GetGroupConfiguration(DataPath dataPath)
   at Xceed.Silverlight.DataGrid.DataGridControl.GroupHeaderFooterConfigurationAdapter.HasHeaders(DataPath dataPath)
   at Xceed.Silverlight.Data.GroupHandler.get_HasHeadersFooters()
   at Xceed.Silverlight.Data.GroupLevelEnumerator.get_AddOrRemoveItems()
   at Xceed.Silverlight.Data.GroupEnumerator.ConvertMoveForRequest(JumpMoveAndFetchParameters parameters)
   at Xceed.Silverlight.Data.MoveConverterEnumerator`1.BeginJumpMoveAndFetch(JumpMoveAndFetchParameters parameters, AsyncCallback userCallback, Object asyncState)
   at Xceed.Silverlight.Data.AsyncParentEnumerator`1.BeginJumpMoveAndFetch(JumpMoveAndFetchParameters parameters, AsyncCallback userCallback, Object asyncState)
   at Xceed.Silverlight.Data.DataSourceEnumeratorBase.BeginMoveAndFetch(Boolean approximateMove, Int64 expectedMoveCount, Int32 expectedFetchCount, AsyncCallback userCallback, Object asyncState)
   at Xceed.Silverlight.Data.EnumeratorExtensions.SyncMoveAndFetch(IAsyncDataSourceEnumerator enumerator, Boolean approximateMove, Int64 expectedMoveCount, Int32 expectedFetchCount, Nullable`1& actualMoveCount, ICollection`1& fetchedItems, RelativeOffset& endPositionOffset, EstimateInt64& totalCount)
   at Xceed.Silverlight.Data.SyncDataSourceEnumerator.MoveAndFetch(Boolean approximateMove, Int64 expectedMoveCount, Int32 expectedFetchCount, Nullable`1& actualMoveCount, ICollection`1& fetchedItems, RelativeOffset& endPositionOffset, EstimateInt64& totalCount)
   at Xceed.Silverlight.Data.EnumeratorExtensions.MoveAndFetch(ISyncDataSourceEnumerator enumerator, Boolean approximateMove, Int64 expectedMoveCount, Int32 expectedFetchCount, ICollection`1& fetchedItems)
   at Xceed.Silverlight.Data.EnumeratorExtensions.MoveAndFetch(ISyncDataSourceEnumerator enumerator, Int64 expectedMoveCount, Int32 expectedFetchCount, ICollection`1& fetchedItems)
   at Xceed.Silverlight.Data.DataSourceEnumeratorWrapper.MoveAndFetch(Int64 expectedMoveCount, Int32 expectedFetchCount, ICollection`1& fetchedItems)
   at Xceed.Silverlight.DataGrid.LayoutManager.MoveHelper(Int64 moveCount)
   at Xceed.Silverlight.DataGrid.LayoutManager.UpdateViewportContent(Boolean pendingTransitionSetup)
   at Xceed.Silverlight.DataGrid.LayoutManager.UpdateViewportContent()
   at Xceed.Silverlight.DataGrid.LayoutManager.OnResetCompleted()