@Nullable
  public Content addCustomTodoView(@NotNull TodoTreeBuilderFactory factory,
                                   @NlsContexts.TabTitle String title,
                                   @NotNull TodoPanelSettings settings) {
    Content content = ContentFactory.getInstance().createContent(null, title, true);
    final TodoPanel panel = myChangesSupport.createPanel(this, settings, content, factory);
    if (panel == null) return null;

    content.setComponent(panel);
    Disposer.register(this, panel);

    if (myContentManager == null) {
      myNotAddedContent.add(content);
    }
    else {
      myContentManager.addContent(content);
    }
    myPanels.add(panel);
    content.setCloseable(true);
    content.setDisposer(new Disposable() {
      @Override
      public void dispose() {
        myPanels.remove(panel);
      }
    });
    return content;
  }
@Nullable
  public Content addCustomTodoView(@NotNull TodoTreeBuilderFactory factory,
                                   @NlsContexts.TabTitle String title,
                                   @NotNull TodoPanelSettings settings)