code: @Override
      public void updateContentRepository(final Iterable<Content> content) {
          Content oldContent = contentColumn.getSelectedItem();
          Content newContent = null;
  
          if (oldContent != null) {
              for (Content c : content) {
                  if (c.getName().equals(oldContent.getName())) {
                      newContent = c;
                  }
              }
          }
          contentColumn.updateFrom(Lists.newArrayList(content), newContent);
          setPreview(PreviewContent.INSTANCE.content_repository());
      }
docs: ------------------------------------------------------ update columns