I tried alt-dragging a field to create a duplicate field. This appeared to work – I could see the selection rect for the object. But when I deselect, the item can’t be seen. It is still there, but I can only select it by drag-selecting across where it is. Simply clicking where the item is doesn’t work, although once it’s selected I can drag it around.
It appears in the Project Browser list and the visibility icon is active, but toggling this makes no difference.