The PreferredCalendarGroupHorizontalExtent indicates the width for the CalendarGroup instances within the controls that arrange their groups horizontally (e.g. XamMonthView and XamDayView). If the available space is less than the preferred extent, the available space will be used so that a group is not wider than the available area. This is required since CalendarGroups are scrolled by group and not pixel based. If the sum of the space required to show all the groups is less than the available space, the groups will be extended to fill the available space. Also, if AllowCalendarGroupResizing is enabled, this property will be updated as the user drags the resizer bar at the right edge of the group.
Target Platforms: Windows 10, Windows 8.1, Windows 8, Windows 7, Windows Server 2012, Windows Vista SP1 or later, Windows XP SP3, Windows Server 2008 (Server Core not supported), Windows Server 2008 R2 (Server Core supported with SP1 or later), Windows Server 2003 SP2