F9 darkens screen

[Glenn Holmer]

I have an unusual issue: lately, when I press F9, instead of whatever
that should mean in the focused window, the entire screen darkens.
Doesn't turn black, just darkens somewhat. Just did it and I can still
type into this window. I don't see anything in my keyboard shortcuts
that would cause it. Anybody else ever seen this?

-- 
Glenn Holmer (Linux registered user #16682) http://www.lyonlabs.org
"The text is only a proposition." -Pierre Boulez