Notes plugin - when does it save?

I've just had a minor run in with the notes plugin. I seem to remember
when I first started usign it being surprised that it retained so much
data over an X restart - i.e. it seemed to keep the data but lose the
positioning. The other day, however, X was killed (not entirely sure
why, nothing logged and it was over night so I didn't see it happen) and
the last couple of days notes were lost. Not a big issue it terms of
data loss, but it does seem to indicate that any new notes are stored in
memory until you log out - is this correct or have I hit a bug of some
sort. Out of interest is there somewhere I could look for the working
file should I wish to try to recover the missing notes? (no doubt
overwritten now if there is one in this case!).

-- 
Paul Tansom | Aptanet Ltd. | http://www.aptanet.com/