In my 2.0.1 the copy/paste from a project to another doesn't work either, let alone the drag & drop.
I solved this way:
Project 1:
Select the scene or map you need ( in the map view, make it active )
share tab: export map file > name it.mapx
Project 2:
Insert Tab > import map
or
catalog > Maps (right click, Import)
Import
(In the import pane, click refresh, for some reason the last map exported is never there.)
select the map/scene (.mapx) > import button.