// invoked when plus button is clicked
private void Button_Click(object sender, RoutedEventArgs e)
{
// initalize the select window selected items
selectWindow.SelectWindowSelectedItems = CopySelectedItems();
selectWindow.ShowDialog();
if (selectWindow.SelectWindowResult)
{
// reset flag
selectWindow.SelectWindowResult = false;
// save the new selection
SaveSelectedItems(selectWindow.SelectWindowSelectedItems);
// convert to text also
ConvertSelectedItemstoText();
// clear any validation errors as no errors
ClearValidationError();
// clear error items as none will exist
ErrorItems.Clear();
}
}