A dated one-shot whose time was moved later while it was snoozed rang a
second time that day, because closing the cycle only asked whether the
date was still ahead. It now keeps the alarm on only for a date after the
day that rang, and a one-shot switched off as its cycle closes lets its
date go.
The date pickers accept every year a stored date can have, so a far date
from a backup can no longer crash the editor. The widget formats its date
with the list's own formatter, and a backup's leftover date on the wrong
kind of alarm is ignored instead of rejecting the file.