How to set up two Mac monitors as a single screen

Macworld
The ability to have two or more external monitors connected to your Mac in Extended Mode is a liberating screen experience, but leads to frustration when each still operates like an independent display.Here we show you how to make the two Extended screens act like one with a few simple changes to your system settings.Without this solution, you can’t have a browser page or application window shared across both screens. Instead, the window is hidden on one of the screens and only pa