private void btnOK_Click(object sender, EventArgs e)
        {
            Hide();
            _updateOkButtonTimer.Stop();
            _updateOkButtonTimer.Dispose();

            DateTime?flagDate = null;

            if (AddFlag)
            {
                flagDate = Utils.ParseFollowUpDate(FollowUpValue, dtpCustom.Value);
            }
            if (AddReminder)
            {
                var rtt = reminderTime.Text;
                if (!rtt.Contains(":") && rtt.Length <= 2) //CASE Parsing eg. 23 or 9
                {
                    rtt += ":00";
                }

                TimeSpan rt;
                if (!TimeSpan.TryParseExact(rtt, @"h\:mm", CultureInfo.InvariantCulture, out rt))
                {
                    rt = DefaultReminderTime();
                }

                flagDate = flagDate.Value.Date + rt;
            }

            var categories = string.Join("; ", this.lstCategories.CheckedItems.Cast <string>());

            _item.DoFollowUp(AddFlag, flagDate, clearFlagOnReply.Checked, AddReminder, MoveToInbox, true, categories: categories);

            Close();
        }