type
  TMyCoolComponent = class(TComponent)
  private
    FAction: boolean;
    FTempAction: boolean;
    procedure SetAction(const Value: boolean);
  protected
    procedure Loaded; override;
  published
    property Action: boolean read FAction write SetAction;
  end;

implementation

{ TMyCoolComponent }

procedure TMyCoolComponent.Loaded;
begin
  inherited;
  Action := FTempAction;
end;

procedure TMyCoolComponent.SetAction(const Value: boolean);
begin
  if csReading in ComponentState then
    FTempAction := Value
  else
   ;// обработка установки значения свойства
end;