private void listBoxTransactions_SelectionChanged(object sender, SelectionChangedEventArgs e)
        {
            // Update buttons than can be effected by ticket selection changes
            OrderEntryCommands.UpdateTicketItemButtons();

            if (SelectionChanged != null)
            {
                SelectionChanged.Invoke(this, e);
            }
        }
 public void ClearSelection()
 {
     listBoxTransactions.SelectedItem = null;
     OrderEntryCommands.UpdateTicketItemButtons();
 }