@Override
  public void setManager(@NotNull ContentManager manager) {
    assert myContentManager == null;
    myContentManager = manager;
    manager.addContentManagerListener(new ContentManagerListener() {
      @Override
      public void selectionChanged(final @NotNull ContentManagerEvent event) {
        initUI();
        if (ContentManagerEvent.ContentOperation.add == event.getOperation()) {
          showContent(event.getContent());
        }
        else if (ContentManagerEvent.ContentOperation.remove == event.getOperation()) {
          hideContent();
        }
      }
    });
  }
@Override
  public void setManager(@NotNull ContentManager manager)