title: Flash Builder error only in active tab after each build
body: <p>I have a problem with Flash Builder 4.7
  I get errors each time I build project. These errors disappear after using "Clean" command. Errors are always about implicit coercion of identical classes. Strange thing is that errors always show in my currently active tab. </p>
  
  <p>Examples:
  "Implicit coercion of a value of type starling.display:DisplayObject to an unrelated type starling.display:DisplayObject"</p>
  
  <p>"Implicit coercion of a value of type flash.display:BitmapData to an unrelated type flash.display:BitmapData"</p>
  
  <p>All of them disappear after using Clean. So I don't know what to do, coz now I have to clean project each time I need to run it. And it takes a lot of time.</p>