I don't know if this is a bug or if this is the way it's intended. But the final date does not display as a tick on a DateAxis. It seems like it should. The change to fix this is as follows.
on line 1516 of DateAxis change from:
while (tickDate.before(upperDate)) {
to
while (!tickDate.after(upperDate)) {
Cheers,
Nathan
unclewaltr@yahoo.com