ACTION parameter on DropObject

Just been hit by a hard to explain issue.

I believed that ALT-Drag means ‘Copy’ in drag and drop
On the Mac, ALT-drag generates an Action = 1 in the DropObject event

Caught that, made a copy.

But on Windows, Alt-Drag gives me an Action = 2
Is this an EXPECTED difference?

Yes
Because ALT+DRAG on Windows means “create a link”

And Ctrl+Drag and shift drag mean something else on Windows
These are platform sensitive