After a short period of training, I got to the point where I can see the third image which I can focus on. However, the differences are very subtile and don't stick out at all :/
Why can't this be an extension? I love the idea and can perfectly imagine this inside a tab of the editor area. This would allow for multiple haystack tabs as well, so switching contexts would be seven easier.
Having to install another IDE (even if it is based on vscode) is a bit of a bummer for me. None the less, keep it up!