Thumb color is not workin

[Koston411]

I tried to change the color of the thumb but I can't.

I'm using Dart 3.3.4 on Android 13.

BeforeAfter(
value: value,
before: Image.file('thumbnail-modified.png'),
after: Image.file(thumbnail2-modified.png'),
direction: SliderDirection.vertical,
trackWidth: 2,
trackColor: Colors.white,
thumbColor: Colors.white,
onValueChanged: (value) {
setState(() => this.value = value);
},
)

The color remains purple (default).