Support » How-To and Troubleshooting » Expandable – Collapsible Lists for Sidebar
9 years, 7 months ago
I use the WP-dTree plugin, but here are a few other ways:
JS Toggle Boxes
Josh Kaufman tutorial
Tutorial at T2
8 years, 10 months ago
The WP-dTree link is now here. It works with WP 2.3.1, too!