anchor.diff:            selected: false,
             labelColor: config.labelColor,
             unselectedLabelColor: config.unselectedLabelColor,
  +          labelStyle: config.labelStyle,
  +          unselectedLabelStyle: config.unselectedLabelStyle,
             child: new _TabLabelBar(
               onPerformLayout: _saveTabOffsets,
               children:  wrappedTabs,
  
positive.code:     this.selected,
      this.labelColor,
      this.unselectedLabelColor,
      @required this.child,
    }) : super(key: key, animation: animation);
  
    final bool selected;
    final Color labelColor;
    final Color unselectedLabelColor;
  
negative.code:           selected: true,
            labelColor: config.labelColor,
            unselectedLabelColor: config.unselectedLabelColor,
            labelStyle: config.labelStyle,
            unselectedLabelStyle: config.unselectedLabelStyle,
            child: wrappedTabs[_currentIndex],
          );
          wrappedTabs[previousIndex] = new _TabStyle(
  