Dear list members

I'm using orgmode according to John Wiegley's tutorial and setup
(Emacs 22.1.50.1, Org 5.07a). One thing annoys me and I don't know if
it is perhaps a mistake in my configuration.

When in the week or day agenda view (C-c aa) and I change the
schedule, priority or state of a task, my todo.org is accordingly
updated but not automatically saved. This leaves a feeling of
uncertainty to a notorious person like me. Is this normal and how can
it be changed? (The not-automatic-saving, not the feeling.)

Thanks for suggestions,

Sven