I have a brand new Macbook Pro Retina, MacBook Pro (Retina, 15-inch, Mid 2015) with Yosemite 10.10.4 (14E46). Every now and then the whole display jerks briefly down and then back up again in place. I haven't found any reference to this online. Any idea why this might be happening?
Based on my experience with Macbooks, I suspect there is either a loose connector, or (sigh) you have a dying chip on the motherboard (probably video controller). Genius Bar should be able to diagnose for you pretty quickly.