One of our users points out that when creating a new event, all of the calendars that are shared with them, including read-only shares, are listed under the choices for "Calendar", and that this clutters this view.
(Most people I work with have their departments share calendars with one another, and therefore have a large list of calendars most of which are read-only to them. I am guessing this is a common behavior.)
When you try to add an event to someone else's calendar, you naturally get a "permission denied" error, so the argument is those choices shouldn't be listed in the first place.
I'm not sure if this is too taste-based to be considered a bug.
ZCS 6.0.2 NE