The DocBook 5 Author actions are the same as the DocBook 4 actions, with the following exception:
Dragging a file from the
Project view
or DITA Maps Manager
view and dropping it into a DocBook 5 document that is edited in
Author mode, creates a link to the dragged file (the
link DocBook element) at the drop location. Dragging an image file from the
default file system application (Windows Explorer on Windows or Finder on Mac OS X, for
example) and dropping it into a DocBook 5 document inserts an image element (the
inlinemediaobject DocBook element with an imagedata child
element) at the drop location, similar to the 
Insert Image Reference toolbar action.