i had the exact same problem a while back. To find a solution i searched and searched google for ages and in the end i had to delete a file/folder, reboot and then all was good.
Problem: can't remember for the life of me what file/folder was.
i think it could be System>Library>MonitorPanels>AppleDisplay.monitorPanels but not 100% on this
What i would do is copy that to your desktop, rename it (remembering the old name). Delete the original (@ System>Library>MonitorPanels>AppleDisplay.monitorPanels) then reboot. If it works os x will create a new one on start up, if it doesn't change the name of the original one back to AppleDisplay.monitorPanels and copy it back to System>Library>MonitorPanels
Good Luck