Further findings below:
1. I entered a wrong path when I set up a linked folder in B. Therefore the shared appointment entered by A didn't show up in B. After I had corrected the path, they showed up correctly in the linked folder in B.
(By the way, in version 4.5, an email would be sent to B for notification of the shared calendar. The receiver could accept or reject the share. In v5.0 rc2 the notification mail was also sent as the following:
<--
The following share has been created:
Shared item: Calendar (Calendar Folder)
Owner: ao608
Grantee:
wingo@example.com
Role: Manager
Allowed actions: View, Edit, Add, Remove, Accept, Decline
-->
I could no longer accept the share right away. I had to manually set up a linked calendar.
2. Outstanding problem: the appointment entered by B in the share calendar was still written to B's personal calendar.
Thanks,
Wingo