So I do use a tiling window manager, but the problem is that to take advantage of it, I'd need the editor to put each buffer in its own (real xorg) window. I couldn't get something working with either vscode or IntelliJ.
One editor that does support it, is kakoune. I forgot about it when writing my previous comment. Each instance can connect to a server, so they can all share registers/buffers/etc. Then you can use tmux or your window manager to create the layout you want.
It's very clever, I actually think it's superior to vim, as you aren't limited to organizing your views inside a single vim "main" window. You could do stuff like kak | browser | kak, and both kak instances share everything.
Unfortunately I can't get used to the kak commands so I'll probably never change. Perhaps neovim will one day implement something similar.
Yeah, Emacs also lets you do that! You can achieve similar workflows via tmux or a tiling window manager as well. It's my favorite way to work! For whatever reason I've never gone down the tiling WM rabbit hole, but I use this kind of thing in Emacs and tmux all the time.