Yeah, maybe a bug then - does it work properly in C2?
Not sure.. C2 is quite different, you can choose the preview browser in the project settings, but for every browser except NW.js, the layout starts as a new tab of the selected browser
with the last active window size as far as I can see... so the size of the canvas is already different to begin with.
NW.js starts with the original settings for the canvas and the layer, but doesn't care about scaling of the canvas at all.
So, hard to compare C2 and C3 at the moment.
C3 doesn't seem to have the browser setting for the project at all, maybe because it's more Chrome orientated at the moment.. I don't know for sure.
Still, It's unclear to me if and when "set canvas size" does anything ...