That has always been possible it just takes patience and should be the last thing you do on the map.
Using the advanced editor allows undo and redo which saves a LOT of frustration and allows you to build them off the main map then cut and paste them in
You have to "sneak up on it" then carefully remove the excess hill showing and avoid the registration hex
and in case anyone's wondering ....NO we didn't do anything on this....what we posted as the features added are all the features added