It's disappointing that i3 is constrained to one window. The ability to replace Microsoft's window manager with i3 and allow linux and windows apps to be nicely tiled together would be amazing.
Now, it ain't tiling, but I once worked (not as the first guy, but took it over as a major project and the hell out of it) was one of the ports of Opebox-ish Windows managers (to be more accurate, really an Explorer replacement shell, not a Windows manager traditionally) to Windows XP to build very stripped down Windows kiosk machines with minimal UI and a lot of control, custom UI, and cool fun features.
Hey, HackWM author here, this might be a better link https://github.com/ZaneA/HashTWM :) Unfortunately it has been largely unmaintained by myself since the initial release, I occasionally pick it up for a day or two but I'm not using it actively anymore. Just happy that some people find a use for it!
X was never designed to work like that. I personally run Visual Studio Code (with a patched X lib to allow Electron to start without graphics acceleration) with the "local window manager" (i.e., Windows itself). Works great.
