Use the UnselectDates method to unselect all dates in the chart. Use the SelectDate property to select or unselect a new date, or to find if a specified date is selected or it is not selected. The SelectedDates property can be used to retrieve all selected dates, or to select a collection of dates. Use the SelectLevel property to specify the area being highlighted when a date is selected. The user can select dates by clicking the chart's header. You can select multiple dates keeping the CTRL key and clicking a new date. The MarkSelectDateColor property specifies the color being used to highlight the selected dates. If the MarkSelectDateColor property is identical with the BackColor property of the Chart object, the selected dates are not shown.