Additive Template Directive
The *Additive: directive defines the order of template definitions.
The Additive directive can have one of the following values:
MOST_RECENT. Only the most recent definition appears.
LEAST_RECENT. Only the least recent (first) definition appears.
MOST_TO_LEAST_RECENT. All definitions appear ordered from most to least recent.
LEAST_TO_MOST_RECENT. All definitions appear ordered from least to most recent.
If this directive is absent, a default value of MOST_RECENT will be assumed.
If this directive is itself multiply defined within a template or appears in several templates that are related by inheritance, only the most recently defined directive in the most derived template will be honored.