Observble<bool> doesn't work in ToReactiveCommand as canExecuteSource

[BR7RKR]

I have the following code:

var canRemove = Observable
            .Merge(SelectedCoordsItem.Select(x => x is not null))
            .ObserveOnUIThreadDispatcher()
            .Where(_ =>
            {
                if (SelectedCoordsItem.Value is null)
                {
                    return false;
                }

                return _savedCoordinates.Contains(SelectedCoordsItem.Value);
            });

        AddNewItemCommand = new ReactiveCommand(AddNewItem).DisposeItWith(Disposable);
        RemoveItemCommand = canRemove.ToReactiveCommand<Unit>(RemoveItem).DisposeItWith(Disposable);

In this case when canRemove translates false value it doesn't turn off my command.

When I turn canRemove into ReactiveProperty everything works fine.

I guess that it is a bug.
If Observable is not a valid source for canExecute in this context, it would be helpful to either:

• restrict the API so that such usage produces a compile-time error, or
• add a remark in the XML documentation clarifying the limitation and the correct usage pattern.