diff --git a/calendar/base/src/calAlarmService.js b/calendar/base/src/calAlarmService.js
index c26767914fce..f58ddc2bdcca 100644
--- a/calendar/base/src/calAlarmService.js
+++ b/calendar/base/src/calAlarmService.js
@@ -75,6 +75,7 @@ function calAlarmService() {
     this.calendarObserver = {
         alarmService: this,
 
+        // calIObserver:
         onStartBatch: function() { },
         onEndBatch: function() { },
         onLoad: function() { },
diff --git a/calendar/base/src/calCalendarManager.js b/calendar/base/src/calCalendarManager.js
index ba1feaba9290..c7e965617b2e 100644
--- a/calendar/base/src/calCalendarManager.js
+++ b/calendar/base/src/calCalendarManager.js
@@ -376,6 +376,7 @@ function errorAnnouncer(calendar) {
     this.storedReadOnly = calendar.readOnly;
     var announcer = this;
     this.observer = {
+        // calIObserver:
         onStartBatch: function() {},
         onEndBatch: function() {},
         onLoad: function() {},
diff --git a/calendar/lightning/content/agenda-tree.js b/calendar/lightning/content/agenda-tree.js
index b19bb3441a3a..9b11ba29a6a3 100644
--- a/calendar/lightning/content/agenda-tree.js
+++ b/calendar/lightning/content/agenda-tree.js
@@ -417,6 +417,7 @@ agendaTreeView.calendarObserver = {
     agendaTreeView: agendaTreeView
 };
 
+// calIObserver:
 agendaTreeView.calendarObserver.onStartBatch = function() {};
 agendaTreeView.calendarObserver.onEndBatch = function() {};
 agendaTreeView.calendarObserver.onLoad = function() {};
@@ -447,6 +448,9 @@ function observer_onModifyItem(newItem, oldItem)
     this.onAddItem(newItem);
 };
 
+agendaTreeView.calendarObserver.onAlarm = function(item) {};
+agendaTreeView.calendarObserver.onError = function(errno, msg) {};
+
 agendaTreeView.setCalendar =
 function setCalendar(calendar)
 {
diff --git a/calendar/lightning/content/calendar-todo-list.xml b/calendar/lightning/content/calendar-todo-list.xml
index b3883b6f9782..8a5ef21e9122 100644
--- a/calendar/lightning/content/calendar-todo-list.xml
+++ b/calendar/lightning/content/calendar-todo-list.xml
@@ -49,6 +49,14 @@
                 this.todoList.rebuildDisplay();
             },
 
+            onAlarm: function onAlarm(aItem)
+            {
+            },
+
+            onError: function onError(aErrNo, aMessage)
+            {
+            },
+
             onCalendarAdded: function onCalendarAdded(aCalendar)
             {
                 this.todoList.rebuildDisplay();
diff --git a/calendar/providers/ics/calICSCalendar.js b/calendar/providers/ics/calICSCalendar.js
index 208a5d92d497..22affe8f1e77 100644
--- a/calendar/providers/ics/calICSCalendar.js
+++ b/calendar/providers/ics/calICSCalendar.js
@@ -772,6 +772,7 @@ calICSObserver.prototype = {
     mCalendar: null,
     mInBatch: false,
 
+    // calIObserver:
     onStartBatch: function() {
         for (var i = 0; i < this.mObservers.length; i++)
             this.mObservers[i].onStartBatch();
diff --git a/calendar/resources/content/calendarManagement.js b/calendar/resources/content/calendarManagement.js
index 75619adf3c66..0c23abd52de3 100644
--- a/calendar/resources/content/calendarManagement.js
+++ b/calendar/resources/content/calendarManagement.js
@@ -225,7 +225,7 @@ function initCalendarManager()
         composite.addCalendar(homeCalendar);
     }
     calMgr.addObserver(calCalendarManagerObserver);
-    composite.addObserver(calCompositeCalendarObserver, 0);
+    composite.addObserver(calCompositeCalendarObserver);
     setCalendarManagerUI();
     initColors();
 }
diff --git a/calendar/resources/content/unifinder.js b/calendar/resources/content/unifinder.js
index 35b27c34d3c3..4ec80eedc2b8 100644
--- a/calendar/resources/content/unifinder.js
+++ b/calendar/resources/content/unifinder.js
@@ -146,6 +146,7 @@ var unifinderObserver = {
         return this;
     },
 
+    // calIObserver:
     onStartBatch: function() {
         this.mInBatch = true;
     },
@@ -170,8 +171,9 @@ var unifinderObserver = {
             refreshEventTree();
     },
     onAlarm: function(aAlarmItem) {},
-    onError: function(aMessage) {},
-
+    onError: function(aErrNo, aMessage) {},
+    
+    // calICompositeObserver:
     onCalendarAdded: function(aDeletedItem) {
         if (!this.mInBatch)
             refreshEventTree();
diff --git a/calendar/resources/content/unifinderToDo.js b/calendar/resources/content/unifinderToDo.js
index 4cf901cf58a7..21540bd582ad 100644
--- a/calendar/resources/content/unifinderToDo.js
+++ b/calendar/resources/content/unifinderToDo.js
@@ -73,6 +73,7 @@ var unifinderToDoDataSourceObserver =
         return this;
     },
 
+    // calIObserver:
     onStartBatch: function() {
         this.mInBatch = true;
     },
@@ -100,8 +101,9 @@ var unifinderToDoDataSourceObserver =
             toDoUnifinderRefresh();
     },
     onAlarm: function(aAlarmItem) {},
-    onError: function(aMessage) {},
+    onError: function(aErrNo, aMessage) {},
 
+    // calICompositeObserver:
     onCalendarAdded: function(aDeletedItem) {
         if (!this.mInBatch)
             toDoUnifinderRefresh();