Question: Dock Has Disappeared - Screen Boundaries Are Wrong
The Dock has disappeared, mostly.
Reboot has not solved the problem. Changing settings under System Preferences > Displays does not resolve it. Changing settings under Dock does not solve it.
The boundaries are wrong. If I change the display to create "More Space", the bottom 15-20% of the screen is no readable by the mouse / trackpad.
To be able to quick launch, I have turned off "Automatically hide and show the Dock". Dock still won't appear, but the top portion of the dock icons become visible, and part of it remains below the screen's viewable area as shown in the screen shot.
iPhone 6, iOS 9.1