//launch form to add an event
        private void addEventToolStripMenuItem_Click(object sender, EventArgs e)
        {
            AddEventForm form = new AddEventForm();
            form.ShowDialog();

            //if the user saved the event, add it to the calendar view
            Appointment newAppt = form.getnewEvent();
            if (newAppt != null) {
                calendarEvents.Add(newAppt);
                calendarView.Invalidate();
                updateLeftPanel();
            }
        }
        //button to add an event
        private void tsAddTaskBtn_Click(object sender, EventArgs e)
        {
            //get the time current selected
            DateTime selectedDateTime = calendarView.SelectionStart;

            //before showing the form, set the start date and time
            //  for the event if the date is valid
            AddEventForm form = new AddEventForm();
            if (selectedDateTime.Year > 2000) {
                form.setStartDate(selectedDateTime);
                form.setStartTime(selectedDateTime);
            }

            //show the form
            form.ShowDialog();

            //if a new event was saved, update the calendar view as well as the left panel
            Appointment newAppt = form.getnewEvent();
            if (newAppt != null) {
                calendarEvents.Add(newAppt);
                calendarView.Invalidate();
                updateLeftPanel();
            }
        }