public FlightBoard()
 {
     InitializeComponent();
     viewM = new FlightBoardVM();
     viewM.PropertyChanged += Vm_PropertyChanged;
     DataContext            = viewM;
 }
 public FlightBoard()
 {
     InitializeComponent();
     this.flightBoard             = FlightBoardVM.Instance;
     flightBoard.PropertyChanged += Vm_PropertyChanged;
 }