How to open multiple Arduino IDE on same computer (Mac)
-Open ‘Applications’ folder.
-Right-click ‘Arduino’, select “Show Package Contents”.
-Open ‘Contents’ folder.
-Open ‘MacOS’ folder.
-Double-click ‘JavaApplicationStub’ to run it.
A Terminal window will open and a new instance of the Arduino IDE will pop up shortly after. Closing the Terminal window will close that instance of Arduino IDE. So minimize it or something.
Test
https://drive.google.com/file/d/0B-aWKAiJsdoNMlNKdHpRVHgwdTA/view?usp=sharing