Gets or sets the extent of the feature which is closest to the base (e.g. a bulb) with a value from -1 to 1. Note: Only some needle shapes respect this property, namely: NeedleWithBulb, RectangleWithBulb, TrapezoidWithBulb, and TriangleWithBulb. Values further from zero than 1 can be used to make this extend further than the normal radius of the gauge.
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
