private void emptySelection() {
    final ProcessingResult processingResult = this.editor.getSearchResult().getProcessingResult();

    if (processingResult == null) {
      target.clear();
    } else {
      target.show(processingResult);
    }
  }
        public void selectionChanged(SelectionChangedEvent event) {
          logger.debug("editor->doclist: " + event.getSelection());

          if (event.getSelection() instanceof ClusterSelection) {
            final ClusterSelection sel = (ClusterSelection) event.getSelection();
            if (sel.isEmpty()) {
              emptySelection();
            } else {
              target.show((Cluster[]) sel.toArray());
            }
          }
        }