它看起来像一个旧的帖子。可能你解决了这个问题但是这里是解决方案：



1.首先在内容中添加一个标题。

2.右键单击新添加的标题和添加主题。



就是这样。

It looks like an old post. May be you solved the issue but here is the solution:

1. First add a heading in the Contents.
2. Right click the newly added heading and add topic.

That''s it.