Google recently made some changes to how the sharing settings in the administrator control panel affect calendars. Previously, these settings only affected primary calendars but now they affect secondary and resource calendars as well.

If you have a secondary calendar or resource embedded in a site you may have to modify these settings to make sure that it’s still visible or has the sharing setting you desire.

– In Gmail, users can delegate access to their account so that other users can read and send messages on their behalf. This is often useful in the scenario of an assistant/PA. However, these users were unable to RSVP to calendar invites in Gmail. Based on your feedback, delegates can now RSVP to events in Gmail on behalf of the account owner.

How to access what’s new:
– In the administrator control panel, go to “Settings”, then “Calendar” and “Sharing options.”
– Gmail delegates can RSVP to an invite in Gmail by clicking ‘Yes’, ‘No’ or ‘Maybe’ in the first section of the invite message, not in the invite header below.

For more information:
http://support.google.com/a/bin/answer.py?hl=en&answer=60765&topic=9201&ctx=topic
https://support.google.com/mail/bin/answer.py?hl=en&answer=138350&ctx=mail