By default, the OverviewMarginsFormat property is empty, meaning that margin dates are displayed according to the current regional settings. The OverviewMarginsFormat property defines how margin dates are displayed in the overview section of the control (for the exOverviewShowSelMargins and exOverviewShowMargins options of the OverviewVisible property). The following screenshot highlights the left and right margins of the current view in bold, and displays in gray the left and right margins of the entire chart:

The OverviewMarginsFormat property supports the following keywords:

• value, specifies the date-time to display
• margin, defines the position of the margin date to display: 0 for the left margin of the whole chart, 1 for the right margin of the whole chart, and 2 or 3 for the left or right margins of the current view

The property also supports predefined constants and functions as listed here. In addition, OverviewMarginsFormat supports exHTML formatting, allowing you to apply different font styles to the displayed date. 

For example:

• "value format `MM/dd`" specifies that the margin dates displayed in the overview section of the control use two digits for the month and two digits for the day, instead of using the regional settings
• "(margin < 2 ? `<fgcolor gray>` : `<b>`) + shortdate(value)" displays the left and right margins of the whole chart in gray, while showing the left and right margins of the current view in bold.