To see the problem:

1. Start Calendar.
2. Go to Week view.

Notice that initially the view is scrolled all the way to the top: Midnight is at the top of the view.  With a typical window size, events after 12 PM or so will not be visible.  This isn't ideal, since most users are unlikely to have events between midnight and 6 AM, but are likely to have events in the afternoon.  I think the initial scroll position should start at 6 AM or so.   (And if the user actually has events that are earlier than that, it would be nice to set the initial scroll position so that they are visible.)