[BUG] Sample code from Handbook is not working

[reactiveui]

[BUG] Sample code from Handbook is not working

[tomasfil]

It seems to be some kind of parallelism issue, because this fixes it:

                OpenDocuments
                    .ToObservableChangeSet()
                    .AutoRefreshOnObservable(document => document.Close)
//This helps
                    .ObserveOn(RxApp.MainThreadScheduler)
                    .Select(_ => WhenAnyDocumentClosed())
                    .Switch()
                    .Subscribe(x => OpenDocuments.Remove(x));

I am giving deeper look into this