Edit: After half day, my wife’s Mac started having the same problem. I have then applied the solution that I found in the Apple
Henge MacBook Air Dock Showcased At CES 2012
We have more CES 2012 Coverage for you. You may have seen the Vertical Henge Dock for MacBooks But they are about to be replaced by the newly announced model for the 11-inch ($55) and 13-inch ($60) Thunderbolt MacBook Airs. This is an amazing looking dock and also looks very stylish which is strange for a device which does allow access to mini Display Port and USB access, rubberized cradle, and a clip to secure your MagSafe cable. You will be able to pre-order this device in mid February .
More CES 2012 Coverage HERE