See eg.
http://wiki.splitbrain.org/wiki:dokuwiki?do=revisions
There are currently two ways of showing the differences between one revision and the current revision. Eg. between 2008/03/09 21:29 + 2008/03/18 20:43.
* Clicking on "the glasses":
http://wiki.splitbrain.org/wiki:dokuwiki?rev=1205094540&do=diff
* Checking two checkboxes and the button "Show differences between selected revisions":
http://wiki.splitbrain.org/wiki:dokuwiki?rev2%5B%5D=current&rev2%5B%5D=1205094540&do%5Bdiff
These two pages should show exactly the same view. But the second one is different (= wrong).