https://github.com/webpack/webpack/issues/247 indicates that the React Developer Tools don't work when using the iframe approach for loading webpack-dev-server (localhost:8080/webpack-dev-server/ in the example you provide).
It might be nice in the note where you mention that approach to also note that the React Dev Tools don't work in that config -- I spent a fair amount of time trying to figure out why I couldn't get them to work because I didn't have that information.
https://github.com/webpack/webpack/issues/247 indicates that the React Developer Tools don't work when using the iframe approach for loading webpack-dev-server (localhost:8080/webpack-dev-server/ in the example you provide).
It might be nice in the note where you mention that approach to also note that the React Dev Tools don't work in that config -- I spent a fair amount of time trying to figure out why I couldn't get them to work because I didn't have that information.