Posting for people that are looking for a solution that works with NW.js (ancient versions used the name Node-Webkit).
First things first, this Chromium Arg is outdated and got depreciated quite a while ago so it's completely useless now.
Currently the only workaround as far as I know, is to do the following:
Steps to open multiple NW.js windows:
- Add the Browser and Keyboard (optional) plugins
- Add the condition on button pressed
- Open as many windows as you like by pressing the selected button
Warning: Don't do the following things:
- Execute on start of the layout
Will create an infinite loop aka "windowception". (You have been warned!)
Open a new window using the browser action open new window
Will create a broken window or limit the amount of windows for unknown reasons.
Execute JS code while the 1st instance of your project still loads (e.g. loader layout)
Will create broken "flickering" window instances, generally results in weird and unexpected behavior.