Observant lot you all are...
There is a new calibration bar at the bottom of the screen...
For those with calibrated monitors you should see 33 distinct bars of brightness.
If either end are continuous black or white then you are not seeing images as they should be.
For those who don't ... click the bar for more information.
From Rick:
The best method I have found for manual calibration is here
reminder: The calibration bar does NOT mean your monitor is correctly calibrated. It just means that the brightness levels are correct, nothing more.
To ensure your monitor is correctly calibrated, the use of a hardware device is necessary. Please do not assume that because you can see all the squares on our calibration bar, that you do not need to use a monitor calibrator. Use of a hardware calibration device is the only way to get it right!
Just cause you can see all the bars does not mean your screen is OK.