Most of these are probably paranoid, not bugs. I haven't done an
exhaustive review to see what really needs it: that would be
time-consuming and require significant familiarity with the Calendar
codebase. This was just a quick check. Anyway, I vote for paranoid
when it comes to using g_signal_connect() regardless. It's dangerous,
and there's no reason to ever leave a signal connected after the user
data object has been destroyed.
Fixes#423
When the all-day checkbox is ticked, transforming to the
UTC timezone may change the dates of the event. On positive
timezone offsets, this happens frequently.
Fix that by only transforming to a timezone when the event
is not marked as all-day.
Fixes https://gitlab.gnome.org/GNOME/gnome-calendar/issues/338