Solved adding this to css block:
// webpack.mix.js
.webpackConfig({
devtool: 'source-map'
})
So, the entire block is:
mix
.sass('resources/styles/app.scss', 'styles')
.sass('resources/styles/editor.scss', 'styles')
.webpackConfig({
devtool: 'source-map'
})
.options({
processCssUrls: false,
postCss:[require('tailwindcss')],
});