title: Generated source files should not be edited in php storm
body: <p>I am editing <code>min.css</code> file in php storm 2016.3 but its showing a message, </p>
  
  <blockquote>
    <p>Generated source files should not be edited. the changes will be lost</p>
  </blockquote>
  
  <p>And not saving what I add.</p>