TouchableWithoutFeedback never fires touch events

I have the following React-Native code which alerts the user that it was pressed, however it does not respond to anything.

I have tried using different Touchable components but none seem to work, the only one is Button but that's not really what I want, I'm building a slider so a button is not really appropriate for this.

Anyway, here's my code:

import React, {Component} from 'react';
import {View, TouchableWithoutFeedback, Alert, Text} from 'react-native';
import styles from './styles.js';
import LinearGradient from 'react-native-linear-gradient';

export default class BrightnessSlider extends Component {
    value: 100;

    constructor(...args) {
        super(...args);
    }

    render() {
        return (
            <LinearGradient start={{x: 0, y: 0}} end={{x: 1, y: 0}} colors={["#222", "#ddd"]} style={styles.brightnessSliderRunnable}>
                <View style={styles.brightnessSliderTrack}>
                    <TouchableWithoutFeedback onPress={() => Alert.alert("Hello World")}>
                        <View style={styles.brightnessSliderThumb} />
                    </TouchableWithoutFeedback>
                </View>
            </LinearGradient>
        )
    }
}

and ./styles.js

import {StyleSheet} from "react-native";

export default styles = StyleSheet.create({
    brightnessSliderRunnable: {
        top: 50,
        height: 9,
        width: width - 20,
        left: 10,
        backgroundColor: "#555",
        opacity: 1,
        elevation: 1,
        borderWidth: 0
        // position: "absolute"

    },
    brightnessSliderThumb: {
        width: 23,
        height: 23,
        borderColor: "#888",
        // opacity: 1,
        borderWidth: 2,
        backgroundColor: "#ffffff",
        position: "absolute",
        top: -7,
        borderRadius: 5,
        elevation: 2
    },
    brightnessSliderTrack: {
        width: "100%",
        elevation: 1,
        borderWidth: 0
    }
});

Thanks for any help