code: @Override
      public void stateChanged(ChangeEvent e) {
          log.debug("getting new collector");
          collector = (CorrectedResultCollector) createTestElement();
          if (collector instanceof CorrectedResultCollector) {
              setUpFiltering((CorrectedResultCollector) collector);
          }
          collector.loadExistingFile();
      }
docs: Invoked when the target of the listener has changed its state. This
  implementation assumes that the target is the FilePanel, and will update
  the result collector for the new filename.
  
  @param e the event that has occurred