I find WP-dTree indispensable for a pretty large site -- it needs the dynamic table of contents so people can find the sub-pages. (http://flcycling.org)

This plugin has given quite a bit of trouble over the years, though. The latest was with Atahualpa 3.6.7: it wouldn't appear at all. I read a post from Flynn giving instructions on setting JS to "external" and editing some code in a file. Well, monkeying around, I set CSS to "external" and WP-dTree sprang back to life! I've toggled it around and confirmed that this will indeed turn WP-dTree on and off. Needless to say, I haven't gone on to modify any code. Thought you'd like to know this.

My larger question is if anyone can suggest another menu system that would provide me the same functionality as WP-dTree. I'm really nervous about my huge dependence on this one plugin.

Thanks for any/all advice.

Do a search for collapsing categories on wordpress.org. There are several such as this one.

Make sure you have the 367 BUGFIX's applied