New Post: Launch ChildWindow when DataGrid row selected

Hi. I have a WPF MVVM Light app in Visual Studio 2015. It has a DataGrid control that shows some records. It has the following binding on SelectedItem:

SelectedItem="{Binding SelectedEmployee}"

On the view model, we detect the change on the SelectedItem and show the details view on that record:

public MyViewModel() 
{
    // Other code
    this.PropertyChanged += (o, e) =>
    {
        if (e.PropertyName == nameof(this.SelectedEmployee))
        {
            ShowEmployeeDetails = (SelectedEmployee != null);
        }
    };
}

However, I would like to open a ChildWindow when this happens -- so that the details view is in a ChildWindow. How would I do this with the WindowContainer and ChildWindow?

P.S. Thank you for these amazing controls :)