Thanks for that link to that thread, NON.
YES, David, that is exactly what it looks like.
I hadn't noticed the horizontal shadow at the bottom of it before because it lines up right where the Blue-ish bottom border of that Registration Window is. But, yeah, the horizontal bottom shadow is also there.
I have attached a Screen Cap of it.
I checked just now and it's still doing the same thing.
I'll poke around this morning and see if any other dropdown menus elsewhere are doing the same thing.
But, it's likely that I'll encounter cases like what's mentioned in that other thread to which NON posted the link.