diff --git a/mozilla/calendar/base/content/calendar-event-dialog.js b/mozilla/calendar/base/content/calendar-event-dialog.js
index 0d91bef138e..33d4f625f70 100644
--- a/mozilla/calendar/base/content/calendar-event-dialog.js
+++ b/mozilla/calendar/base/content/calendar-event-dialog.js
@@ -161,6 +161,10 @@ function loadDialog(item)
             if (item.calendar.uri.equals(calendars[i].uri))
                 calendarList.selectedIndex = i;
         }
+    } else {
+        // no calendar attached to item
+        // select first entry in calendar list as default
+        document.getElementById("item-calendar").selectedIndex = 0;
     }
 
     /* recurrence */
diff --git a/mozilla/calendar/base/content/calendar-item-editing.js b/mozilla/calendar/base/content/calendar-item-editing.js
index 3f4f3541f1e..50771fc1074 100644
--- a/mozilla/calendar/base/content/calendar-item-editing.js
+++ b/mozilla/calendar/base/content/calendar-item-editing.js
@@ -77,6 +77,10 @@ function createEventWithDialog(calendar, startDate, endDate, summary)
     }
     event.endDate = endDate.clone();
 
+    if (calendar) {
+        event.calendar = calendar;
+    }
+
     if (summary)
         event.title = summary;
 
@@ -92,6 +96,10 @@ function createTodoWithDialog(calendar, dueDate, summary)
     const kDefaultTimezone = calendarDefaultTimezone();
     var todo = createToDo();
 
+    if (calendar) {
+        todo.calendar = calendar;
+    }
+
     if (summary)
         todo.title = summary;
 
diff --git a/mozilla/calendar/lightning/content/calendar-management.js b/mozilla/calendar/lightning/content/calendar-management.js
index 2a5d82c550d..65f0b915a67 100644
--- a/mozilla/calendar/lightning/content/calendar-management.js
+++ b/mozilla/calendar/lightning/content/calendar-management.js
@@ -140,6 +140,10 @@ var ltnCalendarViewController = {
         // XXX If we're adding an item from the view, let's make sure that
         // XXX the calendar in question is visible!
         
+        if (!aCalendar) {
+            aCalendar = ltnSelectedCalendar();
+        }
+
         // if we're given both times, skip the dialog
         if (aStartTime && aEndTime && !aStartTime.isDate && !aEndTime.isDate) {
             var event = createEvent();
@@ -364,6 +368,11 @@ var ltnCalendarTreeView = {
 function ltnSetTreeView()
 {
     document.getElementById("calendarTree").view = ltnCalendarTreeView;
+
+    // Ensure that a calendar is selected in calendar tree after startup.
+    if (document.getElementById("calendarTree").currentIndex == -1) {
+        document.getElementById("calendarTree").view.selection.select(0);
+    }
 }
 
 window.addEventListener("load", ltnSetTreeView, false);
diff --git a/mozilla/calendar/lightning/content/messenger-overlay-toolbar.xul b/mozilla/calendar/lightning/content/messenger-overlay-toolbar.xul
index c0e62ca2600..e556541c66c 100644
--- a/mozilla/calendar/lightning/content/messenger-overlay-toolbar.xul
+++ b/mozilla/calendar/lightning/content/messenger-overlay-toolbar.xul
@@ -49,29 +49,59 @@
 
 <overlay xmlns="http://www.mozilla.org/keymaster/gatekeeper/there.is.only.xul">
 
-  <script type="application/x-javascript" src="chrome://calendar/content/calendar-item-editing.js"/>
+  <script type="application/x-javascript" 
+          src="chrome://calendar/content/calendar-item-editing.js"/>
 
   <menupopup id="menu_NewPopup">
-    <menuitem id="ltnNewEvent" label="&event.title.new;" oncommand="createEventWithDialog();"/>
-    <menuitem id="ltnNewTask" label="&todo.title.new;" oncommand="createTodoWithDialog();"/>
+    <menuitem id="ltnNewEvent" label="&event.title.new;" 
+              oncommand="createEventWithDialog(ltnSelectedCalendar());"/>
+    <menuitem id="ltnNewTask" label="&todo.title.new;" 
+              oncommand="createTodoWithDialog(ltnSelectedCalendar());"/>
   </menupopup>
 
   <menubar id="mail-menubar">
-    <menu id="ltnCalendarMenu" label="&lightning.calendar.label;" insertbefore="tasksMenu">
+    <menu id="ltnCalendarMenu" label="&lightning.calendar.label;" 
+          insertbefore="tasksMenu">
       <menupopup id="ltncalendarMenuPopup">
-        <menuitem id="ltnChangeViewDay" label="&lightning.toolbar.dayview.label;" oncommand="switchView('day')"/>
-        <menuitem id="ltnChangeViewWeek" label="&lightning.toolbar.weekview.label;" oncommand="switchView('week')"/>
-        <menuitem id="ltnChangeViewMonth" label="&lightning.toolbar.monthview.label;" oncommand="switchView('month')"/>
+        <menuitem id="ltnChangeViewDay" 
+                  label="&lightning.toolbar.dayview.label;" 
+                  oncommand="switchView('day')"/>
+        <menuitem id="ltnChangeViewWeek" 
+                  label="&lightning.toolbar.weekview.label;" 
+                  oncommand="switchView('week')"/>
+        <menuitem id="ltnChangeViewMonth" 
+                  label="&lightning.toolbar.monthview.label;" 
+                  oncommand="switchView('month')"/>
       </menupopup>
     </menu>
   </menubar>
 
   <toolbarpalette id="MailToolbarPalette">
-    <toolbarbutton id="calendar-new-event-button" class="cal-toolbarbutton-1" label="&calendar.newevent.button.label;" tooltiptext="&calendar.newevent.button.tooltip;" oncommand="createEventWithDialog()"/>
-    <toolbarbutton id="calendar-new-task-button" class="cal-toolbarbutton-1" label="&calendar.newtask.button.label;" tooltiptext="&calendar.newtask.button.tooltip;" oncommand="createTodoWithDialog()"/>
-    <toolbarbutton id="calendar-week-view-button" class="cal-toolbarbutton-1" label="&calendar.weekview.button.label;" tooltiptext="&calendar.weekview.button.tooltip;" oncommand="switchView('week')"/>
-    <toolbarbutton id="calendar-month-view-button" class="cal-toolbarbutton-1" label="&calendar.monthview.button.label;" tooltiptext="&calendar.monthview.button.tooltip;" oncommand="switchView('month')"/>
-    <toolbarbutton id="calendar-day-view-button" class="cal-toolbarbutton-1" label="&calendar.dayview.button.label;" tooltiptext="&calendar.dayview.button.tooltip;" oncommand="switchView('day')"/>
+    <toolbarbutton id="calendar-new-event-button" 
+                   class="cal-toolbarbutton-1" 
+                   label="&calendar.newevent.button.label;" 
+                   tooltiptext="&calendar.newevent.button.tooltip;" 
+                   oncommand="createEventWithDialog(ltnSelectedCalendar())"/>
+    <toolbarbutton id="calendar-new-task-button" 
+                   class="cal-toolbarbutton-1" 
+                   label="&calendar.newtask.button.label;" 
+                   tooltiptext="&calendar.newtask.button.tooltip;" 
+                   oncommand="createTodoWithDialog(ltnSelectedCalendar())"/>
+    <toolbarbutton id="calendar-week-view-button" 
+                   class="cal-toolbarbutton-1" 
+                   label="&calendar.weekview.button.label;" 
+                   tooltiptext="&calendar.weekview.button.tooltip;" 
+                   oncommand="switchView('week')"/>
+    <toolbarbutton id="calendar-month-view-button" 
+                   class="cal-toolbarbutton-1" 
+                   label="&calendar.monthview.button.label;" 
+                   tooltiptext="&calendar.monthview.button.tooltip;" 
+                   oncommand="switchView('month')"/>
+    <toolbarbutton id="calendar-day-view-button" 
+                   class="cal-toolbarbutton-1" 
+                   label="&calendar.dayview.button.label;" 
+                   tooltiptext="&calendar.dayview.button.tooltip;" 
+                   oncommand="switchView('day')"/>
   </toolbarpalette>
 
 </overlay>
diff --git a/mozilla/calendar/lightning/content/todo-list.js b/mozilla/calendar/lightning/content/todo-list.js
index f46a0eab7c7..b82766dd912 100644
--- a/mozilla/calendar/lightning/content/todo-list.js
+++ b/mozilla/calendar/lightning/content/todo-list.js
@@ -16,7 +16,7 @@ function editTodoItem(event)
 
 function newTodoItem(event)
 {
-    createTodoWithDialog();
+    createTodoWithDialog(ltnSelectedCalendar());
 }
 
 function deleteTodoItem(event)