This only works when dropping on an empty workspace area in the IDE. I tested this in 15.0 and 16.0, and it seems to work the same.
In Single Document Mode this can only work if there is no other window opened, since the other windows will take up the complete workspace.
In Multiple Document Mode this will work if you can find some empty space to drop the object.
Dropping the object in an editor of another window will give you the option to insert text relevant to the object (like DDL, description, query, ...).
Can you confirm whether this works for you as well?