In El Capitan this was the equivalent for cut and paste. Does not seem to work in High Sierra, is this a bug or is there some other way of doing the same thing?
Here what happens on my iMac (High Sierra 10.13.1): -
Drag to another folder on the same drive - no green plus - file is moved
Option-drag to another folder on the same drive - no green plus - file is moved
Drag to a different drive - green plus - file is copied
Option-drag to a different drive - green plus - file is copied
I would like to move a file from one drive to another with copying the file and deleting the original.