Only display if headers are present.

One other suggestion for you 😉

If there’s no headers in the content and you therefore won’t be generating anything, don’t render the plugin at all.

Some pages on my site have sub-headings, others don’t, so it only makes sense to display if there’s something useful to show. I’ve done a basic hack for myself, but you might want to make it an option or something. Here’s the code I put in –

https://gist.github.com/4158566

The relevant code is the if block on line 47.

http://wordpress.org/extend/plugins/content-headings-tree/