private void MoveUpOnClick(object sender, RoutedEventArgs e)
{
var oldIndex = this.ViewModel.Windows.IndexOf(this.ViewModel.SelectedWindow);
this.ViewModel.Windows.Insert(oldIndex - 1, this.ViewModel.SelectedWindow);
this.ViewModel.Windows.RemoveAt(oldIndex + 1);
this.ViewModel.SelectedWindow = this.ViewModel.Windows[oldIndex - 1];
}