private void TabCompositions_SelectionChanged(object sender, SelectionChangedEventArgs e)
 {
     try
     {
         TabControl TabControl = sender as TabControl;
         TabItem SelectedTabItem = TabControl.SelectedItem as TabItem;
         this.Composition = Composition.Find(SelectedTabItem.Header.ToString());
         TabTracks.Items.Clear();
         foreach (Track NTrack in Composition.TracksInComposition())
         {
             TabItem ti = new TabItem();
             ti.Header = NTrack.ShortName;
             ti.IsSelected = true;
             TabTracks.Items.Add(ti);
         }
     }
     catch { }
 }