title: Intellij IDEA Cannot Undo
body: <p>I am working on a project at Intellij IDEA. I moved refactored some packages. However I want to undo my changes. When I click revert button it says</p>
  
  <p><code>Cannot Undo</code></p>
  
  <p>and shows a list under that:</p>
  
  <p><code>Following files affected by this action have been already changed</code> </p>
  
  <p>How can I revert my changes because I lost some packages and classes. Does Intellij IDEA keeps them inside a temporary folder?</p>
  
  <p><strong>PS:</strong> I use open jdk 1.6.0 on a 64 bit Ubuntu computer.</p>