Multiple monitors bug with UE 4.14 on Mac

In UE4.14, the Editor freezes and is unresponsive and/or user cannot use any element of the editor in the second display

Regression: this did not occur in previous versions of the Engine: tested in Binary Release UE4.13.1 CL: 3142244 & Binary Release UE4.12.5 CL: 3039270

1. Plug in a second Monitor to a Mac Book Pro or Air (tested on MacBook Air)
2. In Mac's System Preferences>Display>Arrange Displays...
3. Arrange displays so connected display is on top of Macbook display (*see attached image)
4. Open any project in UE4.14

RESULT: Editor freezes and is unresponsive and/or user cannot use any element of the editor in the second display
EXPECTED: Editor to function in both monitors as in all previous versions of the Engine before UE4.14