anchor.diff:  interface and the [classname]#AbstractField# base class.
   [classname]#AbstractField# is the base class for all field components. In
   addition to the component features inherited from
  -[classname]#AbstractComponent#, it implements a number of features defined in
  -[classname]#Property#, [classname]#Buffered#, [classname]#Validatable#, and
  -[classname]#Component.Focusable# interfaces.
  +[classname]#AbstractComponent#, it implements the features defined in the
  +[classname]#HasValue# and [classname]#Component.Focusable# interfaces.
   
   The description of the field interfaces and base classes is broken down in the
   following sections.
  
positive.code: == The [classname]#Field# Interface
  
  The [classname]#Field# interface inherits the [classname]#Component#
  superinterface and also the [classname]#Property# interface to have a value for
  the field. [classname]#AbstractField# is the only class implementing the
  [classname]#Field# interface directly. The relationships are illustrated in
  <<figure.components.fields.field>>.
  
negative.code: image::img/field-interface-hi.png[width=60%, scaledwidth=100%]
  
  You can set the field value with the [methodname]#setValue()# and read with the
  [methodname]#getValue()# method defined in the [classname]#HasValue# interface.
  The actual value type depends on the component.
  
  The [classname]#Field# interface defines a number of properties, which you can
  