public void Refresh()
        {
            _workPeriods = null;
            if (LastWorkPeriod != null)
            {
                WorkPeriodTime = new TimeSpan(DateTime.Now.Ticks - LastWorkPeriod.StartDate.Ticks);
            }

            OpenTicketCount = _ticketService.GetOpenTicketCount();

            if (OpenTicketCount > 0)
            {
                OpenTicketLabel = string.Format(Resources.ThereAreOpenTicketsWarning_f,
                                                OpenTicketCount);
            }
            else
            {
                OpenTicketLabel = "";
            }

            RaisePropertyChanged(() => WorkPeriods);
            RaisePropertyChanged(() => LastEndOfDayLabel);
            RaisePropertyChanged(() => WorkPeriods);

            StartDescription = "";
            EndDescription   = "";

            ActiveScreen = 0;
        }