Hi,
If I understand correctly, you are using TW5 and want a menu on the left side of the story river. The best example is probably the one by Ton Gerner at:
http://tw5topleft.tiddlyspot.com/ It also has option for a top menu.
If you want an example of one that looks something like what you described, I did one based on one of Ton's examples at:
https://dl.dropboxusercontent.com/sh/h8q01y5kygoyhch/AAD0hwllkUF6ivZ5WZ7awzhBa/custom_5-1-8.html Tiddlers go in the menu based on the tag in the tiddlers. In my example, the first, or top, level is tagged Contents. The left menu can be hidden which comes in handy for small mobile screens. I also placed a TOC in the right sidebar so it is available on small screens when the right side bar is placed at the top above the story river. You can download the json file and import it into a new TW to see how it would work for you.
The normal menues don't react as new tiddlers are open but I think someone was trying to do that but I don't have a reference. I don't think any of Ton's were interactive. You'd probably have to search the TiddlyWiki group for TOC or Table of Contents to look for an interactive toc.
Hope that gives you some ideas.
Greg