Hi,

I have noticed, with Mac OS X Panther and Apple Pro Keyboards, it is
somehow possible to bring up a round-cornered adjustment overlay (like
when you press a volume key) in which the "symbol" looks like the one
commonly used to indicate screen contrast. I have only ever seen this
when accidently actuating an unknown combination of keys. I could not
find info about this in Mac Help. Anyone know what the official
shortcuts are?