public void ShowPopup(System.Windows.Forms.Form owner)
        {
            if (popup != null)
            {
                return;
            }

            popup = CreatePopup();
            popup.ChangeSortKey   += ChangeSortKey;
            popup.ChangeFirstChar += ChangeFirstChar;
            popup.RowClicked      += OnRowClicked;
            popup.PopupClosed     += Closed;


            sortKey   = "";
            firstChar = null;

            ChangeSortKey(GetInitialSortKey());
            SetGridRows(sortKey, firstChar);
            SetFirstCharList();
            popup.ShowPopup(owner);
        }
 private void Closed()
 {
     popup = null;
 }