Many thanks for posting about FBX (FileBox eXtender) from http://www.hyperionics.com/
I had downloaded this in 2011, into my "Applications To Trial" folder, but never got around to actually trialling it as I was too busy migrating to another laptop and then forgot about FBX.
After reading your post, I thought "That sounds familiar", did a search of my disk and backups and found the 2011 downloaded file, which has the same checksum as the same/"latest" file version (v2.01.00 64-bit) as is still free + unsupported (discontinued) and available for download on hyperionics.com
So I installed FBX, and am now experimenting with it.
I already like how you can choose to set it to put those rather useful "Roll-Up/Down" and OnTop (Pin) buttons on every Window
- and those are just incidentals!
I had been looking for something like that for ages.
There is an excellent Help file with it and I like how the source code is provided as well.