Use the DisplayRectangle property to determine the client area of the control, which for the UltraMonthViewSingle control is the area inside the control's borders, minus the vertical scrollbar if one is present.
Target Platforms: Windows 10, Windows 8.1, Windows 8, Windows 7, Windows Server 2012, Windows 7, 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