To the o.p.
OMG! As I had said above, the editor window stayed exactly where it was even after closing - using Studio One 4 Pro.
I have not long upgraded to version 5 and guess what: The editor window no longer stays where it was after closing!
So, I have 2 screens and used to leave the console (F3) permanently open and maximised on the second screen. I had set the editor also maximised on the second screen. So, if ever I wanted the editor, all I had to do was press F2 to open it and F2 to put it away again; and all the tine, the console would be ever present: A one button operation i.e. F2.
Now, since upgrading to ver 5, everytime I reopen a song and want to use the editor, it is always docked on the home screen and I have to undock it and maximise it everytime!
I am now as annoyed as you and simply cannot understand why Presonus would change this. Very, very annoying.