When you double click a date entry in the calendar it opens evolution on the
current date instead of the clicked date.

clock.c 1162

static void
calendar_day_activated (ClockData *cd)
{
        /* FIXME: should be able to launch the editor for
         *        the specific day
         */
        calendar_client_launch_editor (cd->client,
                                       CALENDAR_EVENT_APPOINTMENT,
                                       gtk_widget_get_screen (cd->calendar),
                                       NULL);
}