This property can be set to a value between zero and one, where one represents the total height of the containing element.
For example, to situate the area such that it's top edge coincides with the center of the containing element, set this property to .5.
Target Platforms: Windows 10, Windows 8.1, Windows 8, 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