public LapTimesModel()
{
S1 = new PostedTimeCollectionModel();
S2 = new PostedTimeCollectionModel();
S3 = new PostedTimeCollectionModel();
Subscribe(S3.Items, OnCollectionChanged);
Laps = new PostedTimeCollectionModel();
InnerHistory = new ObservableCollection<LapHistoryEntry>();
History = new ReadOnlyObservableCollection<LapHistoryEntry>(InnerHistory);
}