anchor.diff:      if (value == _activeColor)
         return;
       _activeColor = value;
  +    markNeedsPaint();
  +  }
  +
  +  TextTheme get textTheme => _textTheme;
  +  TextTheme _textTheme;
  +  set textTheme(TextTheme value) {
  +    if (value == _textTheme)
  +      return;
  +    _textTheme = value;
       markNeedsPaint();
     }
   
  
positive.code:       ..divisions = divisions
        ..label = label
        ..activeColor = activeColor
        ..onChanged = onChanged;
      // Ticker provider cannot change since there's a 1:1 relationship between
      // the _SliderRenderObjectWidget object and the _SliderState object.
  
negative.code:   @override
    Widget build(BuildContext context) {
      assert(debugCheckHasMaterial(context));
      ThemeData theme = Theme.of(context);
      return new _SliderRenderObjectWidget(
        value: (config.value - config.min) / (config.max - config.min),
        divisions: config.divisions,
        label: config.label,
        activeColor: config.activeColor ?? theme.accentColor,
        textTheme: theme.primaryTextTheme,
        onChanged: config.onChanged != null ? _handleChanged : null,
        vsync: this,
      );
  