In the "Sharing Permissions" tab you can access folders shared by other users, allow other users to see your schedule or send emails in your name.
To allow other users to access one of your mailbox folders, go to the left folder tree, right-click on it and choose the "Sharing" option. For more details on folder sharing, please consult the Folder Sharing section.
The "Allow all users to view my availability" option is included. When this is enabled, all users in your domain will be able to see your "Free / Busy" status, for example when trying to invite you to a meeting (calendar event). Also, when adding or editing permissions for a specific user, the "Read my free / busy status" entry will be allowed and grayed out (not editable).
Global permissions
To define permissions for a specific user / group, click the "+ Add" button.
To edit the permissions for an existing entry click the edit icon found in the "Options" column. In the same column, you have the trash bin icon, which you can use to delete an entry from the permissions list.
Read my free / busy status
If a user editing a calendar event has the "Read free / busy status" permission for the attendee's mailbox, the availability is displayed.
Send emails in my name
When sending a new email message, another "From" address can be set if the user has the "Send Mail As" permission for that mailbox.
In the "Add permissions" wizard, use the "Select" button to access your address book and choose the desired user / group account. If you select a group address, then the respective permissions will apply for all members of that group.
The "Permissions" tab allows you to allow or deny the selected user / group to read your free / busy status or send emails with your account name as the source ("From" field). To see what the user is allowed or disallowed, go to the "Effective permissions" tab.
Open other user's folders
Click the "Subscribe" button or right-click on a folder in the tree and choose Open other user's folders to have access to folders shared by other users. You can either type the email address in the "Shared by" field or click the "Select" button to choose it from the contacts list in your domain.
This option works only for users in the same domain that have set one of the permissions level (except None). If the other user does not have any folders shared for your account, you will receive an error pop-up like the one below.
The folder will appear in the "Other users' folders" section of your folder tree, as shown below.
If you do not wish to see the folders shared by a certain user anymore, close them by right-clicking on the folder displaying the user's name (or one of its sub-folders) and choosing the "Close user" option.