Source-Maps not working with react-hot-loader - reactjs

Question

I'm using react-hot-loader in my react app. I'm using devtool: 'source-maps', but the source-maps don't seem to work. I'm able to view the original source in chrome's dev-tools, but when I get an error, I only see the following:
I've also tried pretty much every other setting for devtool, but I always get this behaviour. What can I do to get source-maps working properly?
Here's my webpack.config.js:
'use strict';
const webpack = require('webpack');
const path = require('path');
const cssModulesLoader =
'css-loader?modules&importLoaders=1&localIdentName=[name]__[local]__[hash:base64:5]';
const cssLoaders = [
// loaders for loading external css
{
test: /\.s[ac]ss$/,
include: path.resolve(__dirname, 'node_modules'),
exclude: path.resolve(__dirname, 'ui'),
loaders: ['style-loader', 'css-loader', 'sass-loader']
},
{
test: /\.css$/,
include: path.resolve(__dirname, 'node_modules'),
exclude: path.resolve(__dirname, 'ui'),
loaders: ['style-loader', 'css-loader']
},
// loaders for custom css
{
test: /\.css$/,
exclude: path.resolve(__dirname, 'node_modules'),
loaders: ['style-loader', cssModulesLoader]
},
{
test: /\.s[ac]ss$/,
exclude: [
path.resolve(__dirname, 'node_modules'),
path.resolve(__dirname, 'ui/src/global.scss')
],
loaders: ['style-loader', cssModulesLoader, 'sass-loader']
},
{
test: /global\.scss$/,
include: path.resolve(__dirname, 'ui/src/global.scss'),
loaders: ['style-loader', 'css-loader', 'sass-loader']
}
];
module.exports = {
devtool: 'source-maps',
entry: {
app: ['babel-polyfill', 'react-hot-loader/patch', './ui/src/index']
},
output: {
path: path.resolve(__dirname, './ui/assets'),
filename: 'bundle.js',
publicPath: 'assets/'
},
module: {
rules: [
{ test: /\.jsx?$/, exclude: /node_modules/, loader: 'babel-loader' },
{ test: /\.json/, loader: 'json-loader' },
...cssLoaders,
{
test: /\.(ttf|eot|woff|svg)/,
include: [path.resolve(__dirname, 'node_modules')],
loader: 'file-loader'
}
]
},
plugins: [
new webpack.ProvidePlugin({
React: 'react'
})
],
devServer: {
historyApiFallback: true,
proxy: {
'/api': {
target: 'http://localhost:48763/',
secure: false
},
'/wsapi': {
target: 'ws://localhost:48763',
ws: true
}
}
}
};