> > Is there anything wrong?
> I think not, but I would really be happy to see an
> understandable explanation of  ifCurtailed.

I think most people get confused here because they don't keep in mind that
when you see a notifier, you always have the option to "proceed". What it
means is that when you see the notifier the guarded block clearly is not
terminated ... yet. It's only when you hit the "abandon" button or close the
notifier that the system knows "ah, okay you want to kill it" and it is only
then that the termination handler is being run.

Cheers,
  - Andreas