private void Btn_AddHeight_Click(object sender, RoutedEventArgs e)
        {
            var wndw = new AddHighHeightWindow()
            {
                Units = _units
            };

            if (!wndw.ShowDialog().Value)
            {
                return;
            }

            lb_h2s.Items.Add(new ListViewItem()
            {
                Content = wndw.H2
            });
        }
        /// <summary>
        /// Prompt user for new high terminal to add
        /// </summary>
        private void Btn_AddHeight_Click(object sender, RoutedEventArgs e)
        {
            var wndw = new AddHighHeightWindow()
            {
                h_1 = h_1
            };

            if (!wndw.ShowDialog().Value)
            {
                return;
            }

            if (h_2s.Count == 0)
            {
                ErrorCnt--;
                Validation.ClearInvalid(lb_h2s.GetBindingExpression(ListBox.ItemsSourceProperty));
            }

            h_2s.Add(wndw.h_2);
        }