Oh—now this is interesting. I tried individually selecting the edges and faces within the box5 prim, and then the edge lines did light up strongly! In fact, as soon as I select just one face, in addition to the edges, then all of the edges turn bright:
Note, however, that the faces selected this way are opaque, whereas faces selected at the next higher level of the tree, as well as those in a selected subfile, are transparent.
Note, however, that the faces selected this way are opaque, whereas faces selected at the next higher level of the tree, as well as those in a selected subfile, are transparent.