View + Single Argument Breaks Primary Links Active Trail

The Primary Links active trail gets lost when a nested menu item links to a view + one argument. When the same menu item is linked to the view path without the argument, the active trail is preserved. Also, if I manually append the argument to the url and load the view, the active trail is still maintained.

This is very similar to this older issue: http://drupal.org/node/235352, which was closed after more or less resolving itself, but I'm using Views 6.x.2.3 on Drupal 6.10. I originally posted this message at the end of that thread - oops.

Example: The active trail is lost when clicking Control Panels in the following menu configuration, where "content/products/id" is the view path:

Fire Systems
-- Control Panels <-- linked to "content/products/id/8"
-- Detection

The active trail preserved for Control Panels with this configuration:

Fire Systems
-- Control Panels <-- linked to "content/products/id"
-- Detection

Manually appending the "/8" and loading the page above preserves the active trail.

I've disabled the only modules (Menu Trails, Menu Block) that I can imagine affecting this and it makes no difference. Any suggestions would be most welcome.