Interpreting Plug-in Information color

I can’t seem to get Voxengo’s MSED (v2.3) plugin to work with Cubase LE (on XP sp3). I can see it in the “Plug-in Information” display, but the only clue to “something different” is that its row is green and its category is “Spacializer”.

I’m hoping the green color is a clue as to why the plugin isn’t available as an insert, send or mastering effect.

However, the Operation Manual doesn’t discuss the meaning of colors in the “Plug-in Information” window, and I find very few references on the web (and none in this forum nor the VST effects forum). Google found some folks who say “brown” means a plugin is broken (I have none of these), and “red” means a plugin supports mastering only (I have one). Most of mine are white, but I also have blue and off-white plugins, all of which function properly.

So can someone clue me on the colors?

Or, to cut to the chase, can someone suggest why Voxengo MSED doesn’t work with LE?