I keep all my research in one folder (called Workspace) in the binder with several sub folders in which I keep relevant research notes. In a second folder (called Construction) I keep the sections of material that I am writing. I have a split screen so that info from my Workspace can be displayed in the left screen & the info from Construction can be displayed in the second. The idea is that I can switch between the sub-folders in each window. I often forget to select the correct screen when I want to change what is being displayed - so I get info that I want to keep on the left screen being displayed in the right screen. Is there a way to have a binder for each screen or to tie a folder to one of the split screens only? I hope that this is clear!!!
If I follow you correctly, there isn’t anything quite like that (nor any plans to do so), but there is the View/Binder Affects/ sub-menu, which provides a few options for setting up how the Binder impacts the split views. The default is, as you note, to always load things where the blue header bar is. But you can change it to ignore that entirely, always loading in the left split for example, or even the opposite of whatever is currently active.
And just to add to that, you can drag items from the binder onto the header bar of an editor as an alternative way of loading things. So, you could set things up so that the binder only affects the left editor, and then load things in the right editor by dragging from the binder to the right editor header bar. (In the next major update, you will also be able to have the outliner and editor both set up in the right split with the outliner navigating the editor there, but that update is still some way off.)
I don’t know if this is a genius idea, an implementation nightmare, or a wacky one-off use-case that would make support curse my name, but why should that stop me?
What if you could hoist the binder to different folders for each editor? Say I select the Research folder while the left editor has focus, and then I hoist the binder to only show research. Then I click into the right editor, click on the Draft folder and hoist it (yes, I know that currently one can’t select Draft if Research is hoisted, but let’s pretend it’s possible). When I click on the left editor again, the ‘hoist’ switches to Research. As such, the binder reflects what I’m working on in each editor until I
Brilliant? Ridiculous? …Obscure? 
Isn’t this already possible, though? I can have my Research folder open in the left split and the Draft folder open in the right. Are you wanting to do more that I’m not getting?
That touches on something that I meant to bring up as well: the editors are very capable navigators in their own right (in some ways even better than the Binder, which is a general purpose tool by definition), especially in Outliner mode. You can drill down into sections go back with the history buttons, or just up in general with the View/Go To/Enclosing Group command. So yes it is possible to “home” a split to a particular area in the Binder and just work with it from there, seamlessly switching between Outliner and text editor view modes as needed to jump around. So in that sense, yes you can already hoist editors by nature of how they work in general, and so of course you can hoist to two different locations. To be perfectly honest, once I get to a general location with the Binder, I often don’t even use it for further navigation, I do a large majority of my navigation within editors themselves, to the point that I often hide the Binder view entirely so that I can focus on the work in the middle.
But I think what rdale is suggesting is that the Documents/Hoist Binder command would not be global, but instead be specific to a split. I’m not sure how well that would work since hoisting doesn’t work backward from the editor content. You hoist from the Binder, so having that command impacted by the split that just so happens to be active would feel odd to me. But maybe I’m so well taken care of by the above described method of working, I don’t really see a need for it. 
Yeah, Ioa’s picking up what I’m dropping.
Yeah, it also might be confusing, “Where did my Characters folder go!” and “Why does my binder keep changing at random!?”
Amber also brings up a good point I’d like to expand upon. select a folder with documents in it and enter scrivenings mode. Lock the editor. Then click on any of those documents in the binder; the editor should jump to the clicked-up document, but if you click on any other documents, nothing happens. So you could do that with a two-editor split, and then you won’t accidentally load the documents into the wrong editor.
I recognise this, and it is a bother.
Usually I have the text I’m working on (an individual document or many documents in scrivening mode) in the left editor. In the right editor I have research notes or pdf:s etc. for reference.
Usually I have to change references a number of times while working on the same text in the left editor. So what I do, I lock the left editor in place so that it doesn’t accidentally change.
When I more occasionally want to change content in the left editor I unlock it.
Not as sophisticated as some of the solutions mentioned before, but it works for me.
Thanks for the input & the suggestions. I have a 'work around" that seems to fit what I need which is I have two documents open at once - one is my Workspace which has all my references & quotations etc in the Binder detail. The other document is my Construction document which has all the chapters & sections etc. in the binder. I can switch from one to the other without having input from one appearing in the other! I’m fortunate that I have a large screen which enables me to have these two documents open side by side. THANKS for the suggestions & input.