Mmmm, yes.  xterm window seems to be using the foreground declared in
the x terminal resources for the background reverse video.

For instance,

Wed Feb  7 11:14:13 on mterm.rse.com ~ A) xrdb -query |grep -i term
XTerm*Foreground:       greenyellow
XTerm*Background:       dimgrey

but, I start another xterm window thusly:

Wed Feb 7 16:47:31 on mterm.rse.com ~ A) exec xterm -bg "black" -fg \
"green" -fn "-*-courier-medium-r-*-*-24-*-*-*-*-*-*-*" -geometry \
96x24+10+600 -ls -title "A Big Black Screen -- Telnet to mac" &

and:

Wed Feb 7 17:16:53 on t982.rse.com /tmp A) exec xterm -dc -bg "black" \
-fg "green" -fn "-*-courier-medium-r-*-*-24-*-*-*-*-*-*-*" -geometry \
105x49+10+600 -ls -title "A Big Black Screen -- already on a Big, Big \
mac" &

and then:

Wed Feb  7 17:08:48 on t982.rse.com /tmp A) lynx -nocolor -book

The background is black, the unhighlighted text is green, and the
highlighted text is a brighter, bolder green.

The (highlighted) selected text is on a _greenyellow_ (_not_ green)
background, while the text appears to still be green (_not_ black).

If I use my mouse to select (cut) unhighlighted text, then the text
becomes green on greenyellow, same as above. _But_, if I use my mouse to
select (cut) _highlighted_ text, then then the text again becomes
green on greenyellow, but the green foreground text is much bolder.

Now, if from one of these green-on-black xterm windows I:

Wed Feb 7 17:07:40 on t982.rse.com /tmp A) exec xterm -dc -fn \
"-*-courier-medium-r-*-*-24-*-*-*-*-*-*-*" -geometry 105x49+10+600 \
-ls -title "A Big Black Screen -- already on a Big, Big mac" &

the new window defaults to greenyellow-on-dimgrey, and if I:

Wed Feb  7 17:08:48 on t982.rse.com /tmp A) lynx -nocolor -book

then I get a lynx where the reverse videos are readable: i.e. the
greenyellow text on dimgrey background reverses to dimgrey (I think,
it's a little hard to see) text on greenyellow background.

However, if I do:

Wed Feb  7 17:08:03 on t982.rse.com /tmp A) lynx -book

I continue to see only one solid sheet of greenyellow.

Now, if I go back to the command prompt in the (still talking about
the greenyellow-on-dimgrey xterm) xterm window, and use my mouse to
select (cut), I get the expected dimgrey (I think, it's a little hard
to see) text on greenyellow background.

Turning back to the green-on-black xterm window, if I use my mouse to
select (cut), I get the green (I think, it's a little hard
to see) text on greenyellow background -- it's almost impossible to
read: the text is only a little different shade than the background.
It's my belief that the text ought to be black on a green background.

I repeated this test starting from nnwest (NetBSD version 1.4.2),
generating a green-text-on-black xterm window from a
greenyellow-text-on-dimgrey xterm, telneting to t982, (no exec on
t982, still telnet'ed from nnwest) lynxing, etc, etc.  All
highlighting, video reversing happened I presume correctly: i.e. the
green text on a black background reversed to black text on green.

The key difference is that the xterm that worked was 1.4.2, while the
ones that didn't were 1.5.

As to why (NetBSD 1.5.1_ALPHA xterm)

Wed Feb  7 17:08:03 on t982.rse.com /tmp A) lynx -book

gives me a sheet of greenyellow, now that's a puzzle. S'pose to be
bold yellow on blue, you say, Geoff. Well, both the
green-text-on-black xterm window and the greenyellow-text-on-dimgrey
xterm window produce the identically same colour, which certainly
seems to be greenyellow, but I can't find any text in there at all.

-Mike