How to move files and folders around quickly with this Apple macOs Sierra Finder "spring open" tip

You probably are aware of macOs Finder capability to "spring open" a folder when dragging/moving a file. If you hover over a folder, it will pop-open to reveal its content. That's very dandy.

What's less dandy is when you go dig into some buried folder and want to move a file back to another folder you had open a moment ago, but now is in turn buried somewhere.

Of course the easy trick is to have two windows open at once, so now you can drag/move your file from one window/folder to another. But there is a BETTER and FASTER trick!

Assuming you had the destination folder opened right before the move - as it's often my case, since I always think a file is in a folder, but noooo, it's somewhere else... So I do a Search, and ah! Ah! Here is the bugger!... But now I need to put the file in another buried folder... grrr... Where the hell was this folder again???

Well, in this case I calmly drag the file over to the Finder Back Arrow. And boom! the Folder I had opened previously pops open! And I delicately drop my file in there.  Whoa
!... FYI the Forward Arrow works as well, as do the various Views Buttons.

Maybe you already knew about this trick? Ah! I just discovered this today! - And I'm a loooongtime Mac user ;)) ...