I had been looking for something to work like Microsft Binder, but withoutn the compatibility problems.
Research Desk was it.
It is a terrific program for opening up different sections of large documents in different formats.

For example, I am working on a PhD and at times need to see each chapter with a separate file of stuff I want to put in and another of stuff I have cutout - that's one RD file.

Another file is all of the chapters at the same time.

Yet another is all of the statistical chapters, or all of the chapters in each section.

RD Opens up all of the original documents so if I work in All Chapters one day and save the changes, RD opens the saved file when I work in One Section the next day