title: Eclipse - Pydev, doesn't recognize not imported methods
body: <p>I have Eclipse Version: 4.2.1 and PyDev version 2.7.1 installed on my 64-bit Ubuntu.
  I am using Python 2.7 and I have this problem with Eclipse that it doesn't recognize my un-imported methods. For example if I write a code like this:</p>
  
  <pre><code>def main():
    myfiles = os.listdir('src')
  
  if __name__ == '__main__':
    main()
    print'done!'
  </code></pre>
  
  <p>I get this error:</p>
  
  <pre><code>Traceback (most recent call last):
    File "tset.py", line 5, in &lt;module&gt;
      main()
    File "tset.py", line 2, in main
      myfiles = os.listdir('src')
  NameError: global name 'os' is not defined
  </code></pre>
  
  <p>which is a pretty obvious error because I didn't write "import os" at the beginning of my code. My problem is that Eclipse doesn't highlight these errors for me anymore. Either I have to find them by myself or I will find out about them when I run my code.
  My Eclipse was working fine before but I don't know what did I change that this happened.</p>
  
  <p>I should also mention that I have "lib" folder in my project and in that folder I have a few of my own modules and I have added the "lib" folder to PYTHONPATH of my project. And the code that I am running is in another folder named "test" and that's not in the PYTHONPATH.</p>