Hi, I tried that but it has not solved anything.
I added the argument to the "package.json" file and then saved the file.
I did the test but the window keeps losing the configuration.
I deleted the argument from the "package.json" file and saved it again.
I have installed the previous version of NWjs 0.42.4 with this version everything works as usual and the window does not lose the configuration. In the gif you can see how I adapt the window, then run again and the window remains.
I think the latest version of NWjs has a bug.
https://giphy.com/gifs/TiCnncOqV66zA5XM4K
Alright I looked into this and it's actually not a bug. Inside the package.json file (or package-preview.json for C2 preview), is a property called: "position": "center",. This was partly broken during the NW2 switch and has been fixed in NWjs v0.42.5.
The indented behavior has always been to center the preview window on startup and in order to keep it in the same position, you'd just have to keep the preview window open and refresh it when needed.
If you really want to restart the preview window over and over again, just remove "position": "center", property from the package.json file (or package-preview.json for C2 preview).