private void OnPlaylistSelectionChanged(object sender, SelectionChangedEventArgs e)
        {
            ListBox playlistListBox = (ListBox)sender;

            if (playlistListBox.SelectedItem == null)
            {
                return;
            }

            Playlist selectedPlaylist = (Playlist)playlistListBox.SelectedItem;

            if (selectedPlaylist.Tracks == null)
            {
                //Expand the playlist to include tracks.

                PlaylistTrackList playlistTracks = SpotifyClientService.Client.GetPlaylistTracks(selectedPlaylist);
                selectedPlaylist.SetPlaylistTracks(playlistTracks);
            }

            _viewModel.SelectedPlaylist = selectedPlaylist;

            //Reinitialize the Atlas control.
            RaiseSelectionChangedEvent(sender, e);
        }