File changes not watched by Webpack on Ubuntu

I'm running into my console a npm script using :

     webpack-dev-server --progress --colors --port 8080

This is supposed to watch and rebuild a bundle.js file on each change. When I use gedit or vim, this works, but when I use Webstorm 10, it does not. Probably the automatic save stuff makes not enough noise to the system.

I did add the inotify stuff

fs.inotify.max_user_watches = 524288

And there is no more the warning message at the startup. But nothing changed and webpack watch doesn't work. Is there any clue ?