Code Editors, Split Screens, and More!

First, let me set up the problem:

I'm using my laptop, taking a class, and I've got my workspaces right along side. I'm programming and everything is going smooth, but then Nick Petit does something on-screen that I can't quite see, so I move to enlarge the video. Except now one screen is much larger than the other and I can't see my workspaces very well.

The solution:

Either a website with two frames, like how googlegooglegooglegoogle.com used to have four, or some sort of application similar to the way you can make the newer smartphones go splitscreen. Ideally, this would involve the screens changing size simultaneously, with darker colors to denote which screen you are using, as well as a constant refresh option for either screen

So my Question:

Are there code editors that do this? Do you know of any pre-existing websites that might work this way? And if I were to make my own, would a website or an application work better? What sort of coding experience would be useful to make this sort of thing? And finally, is anyone else finding they have the same problem or is it just me?