TActionLink descendants call IsEnabledLinked to determine whether they need to propagate changes to the Enabled property of the action so that they are reflected by the client object. When IsEnabledLinked returns true, the action controls the Enabled property: Changes to the Enabled property of the action are reflected by changes to the corresponding property of the client object. When IsEnabledLinked returns false, the client object does not reflect the Enabled property of its action, either because it does not have a corresponding property, or, more commonly, because it manages the value of its corresponding property independently. 

As implemented in TActionLink, IsEnabledLinked merely checks that the Action property specifies a descendant of TCustomAction (that is, it is an action that has an Enabled property). Descendant classes override IsEnabledLinked to determine whether the Enabled property is linked with the appropriate client property. 

Enabled 

Enabled 

SetEnabled 

Action