Exception raised at wpf designer level

Question

Good evening I have a problem with my XAML designer. I find this error:

System.ArgumentNullException

The value can not be null.

Parameter name: remoteValues

to Microsoft.Expression.DesignHost.Isolation.Remoting.LocalNotifyingEnumerable`2..ctor (IRemoteNotifyingEnumerable`1 remoteValues, Func`2 converter)

to Microsoft.Expression.DesignHost.Isolation.Remoting.LocalDesignerView.Microsoft.Expression.DesignHost.IDesignerView.get_RelatedDocumentPaths ()

to Microsoft.Expression.DesignHost.IsolatedDesignerService.IsolatedDesignerView.CreateDesignerViewInfo (CancellationToken cancelToken)