How to make a secondary menu show up when looking at a node?

Hi,
The taxonomy on my site is like this:

Percussion (Parent Taxonomy)
- Snare Drums (taxonomy)
-- Sticks (taxonomy)
--- Stick #123 (node)
--- Stick #456 (node)
-- Stands (taxonomy)
--- Stand ABC (node)
--- Stand DEF (node)

I have menu block set up so that the starting location is Secondary (so, Snare Drums / Timpani / etc under Percussion). Max depth is unlimited, and the sub-menu is always expanded. Clicking around the taxonomy pages works perfectly -- I see the percussion area when I'm in percussion, and when I click over to Brass I see all the sub-sections of Brass instead.

However! When I click in to an actual node, the whole block disappears. How can I make it stay?

I gather this might have something to do with 'active-trail', and I have installed and configured Menu Trail and still get the same thing. Honestly, though, I have no idea if my problem is in this module or that one...

Thanks for any help you can offer!