webpack-dev-server does't overwrite files after save changes

I useing npm start when server is up, I save changes page doesn't reload, where is problem? webpack --watch working good, someone can help me :) I don't understand why is that.

  "scripts": {
    "test": "echo \"Error: no test specified\" && exit 1",
    "start": "killall -KILL node; webpack-dev-server --inline --hot"
  },