Distinguish instances of GUI file manager by color

[Richard Owlett]

I'm setting up a new machine and copying files from the old machine's 
home directory. At the same time I'm creating a new directory structure 
to better match how I work.

I found it expedient to have at least three instances of the file 
manager open - [one for source directory and at least two for 
destination (sub)directories].

Suggestions?
Is it even possible?

Brief web search was not encouraging. But my search terms may have been 
the problem. Suggested search terms?

TIA