If you have an external display hooked up to a MacBook, using the Macbook keyboard’s brightness keys will change the laptop display. The external keyboard will

If you have an external display hooked up to a MacBook, using the Macbook keyboard’s brightness keys will change the laptop display. The external keyboard will change the external display (if attached). Ctrl + brightness key inverts the behavior for both external and internal. http://finerthings.in/mac/tips-for-changing-brightness-on-macbook-external-displays/ http://finerthings.in/mac/tips-for-changing-brightness-on-ma...