title: Eclipse does't shows errors in Package Explorer
body: <p>My Eclipse stoped showing errors in project explorer window. Currently in I ask Eclipse run class I got message:</p>
  
  <pre><code>Error in Workspace
  
  Errors exist in required project(s)
  
  Prog
  
  Proceed with lounch?
  </code></pre>
  
  <p>And I have no possibility to check where are these errors are. How to fix this problem?</p>