When set to true (default), and the edit portion is cleared, the new value is assumed to be Color.Empty.
When set to false and the edit portion is cleared, the value of the DefaultColor property is applied instead.
Note: In the case where the DefaultColor property is set to Color.Empty, clearing the edit portion will result in a value of Color.Empty, regardless of the value of the AllowEmpty property.
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