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.
The best method I have found for manual calibration is here
Just cause you can see all the bars does not mean your screen is OK.