Erm, we don't seem to have a button called "diff", easiest way to compare versions is to select the two revisions you want to view via radio buttons on the history page and then hit "compare selected versions". Good idea developing it there anywayI've put up the draft on the wiki so changes can be centrally coordinated rather than different Hex members keeping different copies, with the differences between copies being possibly unclear. You can view an ongoing list of changes here (click "diff" to see the difference between one revision and the last).