Enlarge to see the text
Edit in any of the main 3D or 2D views then mouse over the smaller 3D view and it'll update.
The large 3D window and the 2D views are an on-grid instance vmf and the small window is the main map vmf where the func_instance is at a horrible angle.
Just make sure everything in the instance is a func_detail if you're rotating it or you'll regret it!