We have a shared calendar that was created with one user having all rights and everyone else read-only. Now when the creator/owner of the calendar sends a sharing update to a specific user (already on the list with read rights) so that the user can have all rights, the user getting the update gets an email from " " (the sender's name is blank) stating that the rights have changed. But there is no actual message.

Also when the calendar creator tries to delete users who are on the sharing list, they reappear after he closes and reopens the calendar.

Any idea what's up & how to get the other user to also have all rights so that he can post to the calendar ?