Chrome Version       : 51.0.2704.79 m
URLs (if applicable) : N/A
Other browsers tested: N/A
  Add OK or FAIL, along with the version, after other browsers where you
have tested this issue:
     Safari:
    Firefox:
         IE:

What steps will reproduce the problem?
(1) Download this app: https://chrome.google.com/webstore/detail/advanced-rest-client/hgmloofddffdnphfgcellkdfbfbjeloo?hl=en-US
(2) Open an instance of the app
(3) Open a second instance of the app
(4) Close the first window
(5) Open a third instance of the app

What is the expected result?
A new window opens

What happens instead?
The last opened window is focused

Please provide any additional information below. Attach a screenshot if
possible.

I am not an app developer, so I do not have any sort of minimal example. I reported this as a bug to the original developer of the app I am using as an example and was told it was potentially a bug in Chrome & to report it to the Chromium team. 
Original bug report here:
https://github.com/jarrodek/ChromeRestClient/issues/687