diff --git a/include/class.task.php b/include/class.task.php
index 55f0152896da820a1897076c884596659bc462e4..fe1e71921766846433ec0e245adcc2ce1ae7690a 100644
--- a/include/class.task.php
+++ b/include/class.task.php
@@ -1189,7 +1189,7 @@ class Task extends TaskModel implements RestrictedAccess, Threadable {
         global $cfg;
 
         if (!$entry instanceof ThreadEntry
-            || !($recipients=$this->getThread()->getParticipants())
+            || !($recipients=$this->getThread()->getRecipients())
             || !($dept=$this->getDept())
             || !($tpl=$dept->getTemplate())
             || !($msg=$tpl->getTaskActivityNoticeMsgTemplate())
diff --git a/include/class.thread.php b/include/class.thread.php
index 343b3e9005689e01a11ef5611e3a00179b776f82..a9485d0b85477e339e6d4fc3cbe4ae978a15abb6 100644
--- a/include/class.thread.php
+++ b/include/class.thread.php
@@ -263,6 +263,17 @@ implements Searchable {
         return $this->_participants;
     }
 
+    // MailingList of recipients (collaborators)
+    function getRecipients() {
+        $list = new MailingList();
+        if ($collabs = $this->getActiveCollaborators()) {
+            foreach ($collabs as $c)
+                $list->addCc($c);
+        }
+
+        return $list;
+    }
+
     function getReferral($id, $type) {
 
         return $this->referrals->findFirst(array(
diff --git a/include/class.util.php b/include/class.util.php
index a3bc2305d130c8b7bf5885cc4df99f4dcf1cae22..e78c00d1d56347ccacdc1c0ca0702bc91ea65ba1 100644
--- a/include/class.util.php
+++ b/include/class.util.php
@@ -5,6 +5,7 @@ require_once INCLUDE_DIR . 'class.variable.php';
 // Used by the email system
 interface EmailContact {
     function getId();
+    function getUserId();
     function getName();
     function getEmail();
 }
@@ -28,6 +29,10 @@ implements EmailContact {
         return $this->contact->getId();
     }
 
+    function getUserId() {
+        return $this->contact->getUserId();
+    }
+
     function getEmail() {
         return $this->contact->getEmail();
     }