The MarkSelectDateColor property specifies the color being used to highlight the selected dates. 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. Use the SelectLevel property to specify the area being highlighted when a date is selected. Use the SelectDate property to select dates programmatically. By default, the MarkSelectDateColor is blue ( as your control panel indicates the color for the selected items ). The selected dates are not marked if the MarkSelectDateColor property has the same value as BackColor property if the Chart object. The MarkTodayColor property specifies the color to mark the today date. Use the LevelFromPoint property to get the index of the level from the cursor. Use the DateFromPoint property to retrieve the date from the cursor.

In the following screen shot the red lines marks the selected dates ( June 20 and June 28 ):

The following screen show how a new date gets selected once the user clicks a date in the chart's header: