Mxsmanic writes:

Odd that Reality XP includes this since it
apparently isn't part of the instrument itself.

Actually, I've learned from the Reality XP forum that this was a special for
Dreamfleet's Piper Dakota instrument panel, and once it was in, they decided
to leave it as an option for the instrument in case anyone else wanted it.
Once again, a Reality XP instrument turns out to behave just like the real
thing.