is it possible with Geany to reverse the order of lines in a document?
Well it is possible on the command line
$ man tac
So just define a Custom Command to tac and then:
Select text, Right Mouse->Format->Send Selection To->tac
-- Andrew Janke (a.janke@gmail.com || http://a.janke.googlepages.com/) Canberra->Australia +61 (402) 700 883