private void BtnView_Click(object sender, RoutedEventArgs e)
        {
            VehicleWindow vehicleWindow = new VehicleWindow(Journeys, FuelPurchases, Services, false)
            {
                Owner       = this,
                DataContext = selectedVehicle
            };

            vehicleWindow.ShowDialog();
        }
        private void BtnAdd_Click(object sender, RoutedEventArgs e)
        {
            if (Online)
            {
                VehicleWindow vehicleWindow = new VehicleWindow(Journeys, FuelPurchases, Services, true)
                {
                    Owner       = this,
                    DataContext = new Vehicle(Vehicles.FindId())
                };

                vehicleWindow.ShowDialog();
            }
            else
            {
                MessageBox.Show("Limited 'View Only' Capabilities on Offline Mode");
            }
        }