A long expression that indicates the height of the chart's overview area.
By default, the OverviewHeight property is 24 pixels. If
the OverviewHeight property is 0, or the OverviewVisible
property is False, the chart's overview area is hidden. The OverviewBackColor
property specifies the background color for the overview area. Use the OverviewSelBackColor
property to change the visual appearance of the selection in the overview
area. The OverviewToolTip property
specifies the format of the tooltip being displayed when the cursor hovers the
overview area. The OverviewLevelLines
property indicates the index of the level that displays the grid lines in the
overview area.