Ember.js input focus lost on valueBinding

I'm creating application with ember.js + Rails

Here is my templates/application.emblem:

#wrapper
  article.new
    = view Ember.TextField valueBinding='newPostName'

the problem is, that after clicking on input, and pressing any key, focus on that input is lost.

It happens only first time and I wonder why. After clicking again, I can type any string and everything works fine.

Here is my Gemfile:

gem 'ember-rails'
gem 'ember-source', '~> 1.13.5'
gem 'ember-emblem-template'
gem 'emblem-source'

via Chebli Mohamed