diff --git a/calendar/inc/class.bocal.inc.php b/calendar/inc/class.bocal.inc.php
index e9991de4dd..97e17a2fe8 100644
--- a/calendar/inc/class.bocal.inc.php
+++ b/calendar/inc/class.bocal.inc.php
@@ -21,6 +21,12 @@ define('HOUR_s',60*60);
 define('DAY_s',24*HOUR_s);
 define('WEEK_s',7*DAY_s);
 
+/**
+ * Gives read access to the calendar, but all events the user is not participating are private!
+ * Used be the addressbook.
+ */
+define('EGW_ACL_READ_FOR_PARTICIPANTS',EGW_ACL_CUSTOM_1);
+
 /**
  * Class to access all calendar data
  *
@@ -271,7 +277,7 @@ class bocal
 		$users = array();
 		foreach($params['users'] as $user)
 		{
-			if ($params['ignore_acl'] || $this->check_perms(EGW_ACL_READ,0,$user))
+			if ($params['ignore_acl'] || $this->check_perms(EGW_ACL_READ|EGW_ACL_READ_FOR_PARTICIPANTS,0,$user))
 			{
 				if ($user && !in_array($user,$users))	// already added?
 				{
diff --git a/calendar/inc/class.uical.inc.php b/calendar/inc/class.uical.inc.php
index ad33a2439c..649bd5a2ef 100644
--- a/calendar/inc/class.uical.inc.php
+++ b/calendar/inc/class.uical.inc.php
@@ -189,13 +189,13 @@ class uical
 				foreach($GLOBALS['egw']->accounts->member($owner) as $member)
 				{
 					$member = $member['account_id'];
-					if (!$this->bo->check_perms(EGW_ACL_READ,0,$member))
+					if (!$this->bo->check_perms(EGW_ACL_READ|EGW_ACL_READ_FOR_PARTICIPANTS,0,$member))
 					{
 						$no_access_group[$member] = $this->bo->participant_name($member);
 					} 
 				}
 			}
-			elseif (!$this->bo->check_perms(EGW_ACL_READ,0,$owner))
+			elseif (!$this->bo->check_perms(EGW_ACL_READ|EGW_ACL_READ_FOR_PARTICIPANTS,0,$owner))
 			{
 				$no_access[$owner] = $this->bo->participant_name($owner);
 			}