Outlook allows the user to mark items in folders as "private". (Evolution allows this in Calendar and Task folders, but not Contact or Mail folders.) Private items are not supposed to show up when other users view the folder, unless they have been given explicit permission to view private items in the Delegates dialog.

Bizarrely, Exchange does not actually enforce this. Thus, when a user subscribes to another user's folder, Connector has to check whether or not the user is supposed to be able to view private items, and filter them out if not.

The information about who can view private items is stored with the delegates data on the other user's mailbox. ExchangeHierarchyForeign checks that data, and sets its hide_private_items flag accordingly. (If it cannot read the delegates data, it assumes that the user is not allowed to view private items.)

ECalBackendExchange and EBookBackendExchange check the hide_private_items flag on the ExchangeHierarchy of the folder they are working with, and set their private_item_restriction fields accordingly:

	hier = e_folder_exchange_get_hierarchy (cbex->folder);
	if (hier->hide_private_items) {
		cbex->private_item_restriction =
			e2k_restriction_prop_int (
				E2K_PR_MAPI_SENSITIVITY, E2K_RELOP_NE, 2);
	} else
		cbex->private_item_restriction = NULL;

That field is incorporated as part of the restriction in every SEARCH that they do, so that if hide_private_items was set, the private items will be excluded from the SEARCH results.