I'll upload a test file in a moment when I can access the other PC, I want to be sure it happens with an empty project;
Also by installing, you mean download the new version and drop the folders in the NWjsforC2 directory (the one created by C2 installer) or this is a different method of installation? Thanks
EDIT : I made an empty project (854x480, letterbox scale integer, not resizable, NWjs V0.47, C2 r275)
with a text indicating dimensions of viewport, browser and NWjs, same issue happened, based on the text viewport and browser inner size are almost the same, yet there are borders around it :
drive.google.com/file/d/13id6x3ygOSt6UgpGremQ9eRfLgaMi3t0/view
Tell me if you need anything else
Also a friend with a screen the same size of mine tested it , and this time it scaled down, I don't get what is happening