code: def dragdrop(self, chviewer, uris):
          
          # find out our channel
          chname = self.get_channel_name(chviewer)
          self.open_uris(uris, chname=chname)
          return True
docs: Called when a drop operation is performed on a channel viewer.
          We are called back with a URL and we attempt to (down)load it if it
          names a file.