'Declaration Public Class FilterButton Inherits FilterButtonBase
public class FilterButton : FilterButtonBase
To actually show filter buttons inside field labels, set the FieldLayoutSettings's FilterUIType property to 'LabelIcons'.
Target Platforms: Windows 10, Windows 8.1, Windows 8, Windows 7, Windows Server 2012, 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