title: Emacs ess auto-complete
body: <p>I am a R user, I want to use R in emacs. But, I am in trouble with customizing ess in emacs. I have installed the auto-complete packages and the latest ess in my emacs. But when I run r in emacs, the auto-complete don't work well. 
  When I type app, I suppose to show like the image in (<a href="http://www.emacswiki.org/pics/static/ess-ac3" rel="nofollow">http://www.emacswiki.org/pics/static/ess-ac3</a>) , but in my emacs neither of the auto-complete nor the yellow part shows.</p>
  
  <p>My OS: ubuntu 12.04 amd64</p>
  
  <p>my ~/.emacs file</p>
  
  <pre><code>;; Auto-complete
  (add-to-list 'load-path "~/.emacs.d/site-lisp")
  (require 'auto-complete-config)
  (add-to-list 'ac-dictionary-directories "~/.emacs.d/site-lisp/ac-dict")
  (ac-config-default)
  ; ess-site
  (add-to-list 'load-path "/usr/share/emacs/site-lisp/ess")
  (require 'ess-site)
  (setq ess-eval-visibly-p nil)
  (setq ess-ask-for-ess-directory nil) 
  </code></pre>