The larger the radius of the edges of a background image, the larger the value of this property should be.
That area can not contain text or an image, so, it is similar to the bottom-padding.
If this property is set to 0, then the height of the control is defined by the value of the MaxHeight property.
Requirements
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