diff --git a/content/events/src/nsDOMEvent.cpp b/content/events/src/nsDOMEvent.cpp
index 3984ef9654e..17949c60851 100644
--- a/content/events/src/nsDOMEvent.cpp
+++ b/content/events/src/nsDOMEvent.cpp
@@ -50,8 +50,8 @@ static char* mEventNames[] = {
   "mouseout", "mousemove", "keydown", "keyup", "keypress",
   "focus", "blur", "load", "unload", "abort", "error",
   "submit", "reset", "change", "select", "input", "paint" ,"text",
-  "create", "destroy", "command", "broadcast", "commandupdate", "dragenter", "dragover", "dragexit",
-  "dragdrop", "draggesture"
+  "create", "close", "destroy", "command", "broadcast", "commandupdate",
+  "dragenter", "dragover", "dragexit", "dragdrop", "draggesture"
 }; 
 
 nsDOMEvent::nsDOMEvent(nsIPresContext* aPresContext, nsEvent* aEvent) {
@@ -855,6 +855,8 @@ const char* nsDOMEvent::GetEventName(PRUint32 aEventType)
     return mEventNames[eDOMEvents_focus];
   case NS_BLUR_CONTENT:
     return mEventNames[eDOMEvents_blur];
+  case NS_XUL_CLOSE:
+    return mEventNames[eDOMEvents_close];
   case NS_PAGE_LOAD:
   case NS_IMAGE_LOAD:
     return mEventNames[eDOMEvents_load];
diff --git a/content/events/src/nsDOMEvent.h b/content/events/src/nsDOMEvent.h
index 1b564253cb8..decc8be1f40 100644
--- a/content/events/src/nsDOMEvent.h
+++ b/content/events/src/nsDOMEvent.h
@@ -70,8 +70,9 @@ public:
     eDOMEvents_select,
     eDOMEvents_input,
     eDOMEvents_paint,
-	  eDOMEvents_text,
+    eDOMEvents_text,
     eDOMEvents_create,
+    eDOMEvents_close,
     eDOMEvents_destroy,
     eDOMEvents_command,
     eDOMEvents_broadcast,
diff --git a/content/events/src/nsEventListenerManager.cpp b/content/events/src/nsEventListenerManager.cpp
index c96aa2f2608..d12ca2aa7b8 100644
--- a/content/events/src/nsEventListenerManager.cpp
+++ b/content/events/src/nsEventListenerManager.cpp
@@ -388,6 +388,10 @@ nsresult nsEventListenerManager::GetIdentifiersForType(nsIAtom* aType, nsIID& aI
     aIID = kIDOMMenuListenerIID; 
     *aFlags = NS_EVENT_BITS_MENU_CREATE;
   }
+  else if (aType == nsLayoutAtoms::onclose) {
+    aIID = kIDOMMenuListenerIID; 
+    *aFlags = NS_EVENT_BITS_XUL_CLOSE;
+  }
   else if (aType == nsLayoutAtoms::ondestroy) {
     aIID = kIDOMMenuListenerIID; 
     *aFlags = NS_EVENT_BITS_MENU_DESTROY;
@@ -1268,6 +1272,7 @@ nsresult nsEventListenerManager::HandleEvent(nsIPresContext* aPresContext,
       break;
 
     case NS_MENU_CREATE:
+    case NS_XUL_CLOSE:
     case NS_MENU_DESTROY:
     case NS_MENU_ACTION:
     case NS_XUL_BROADCAST:
@@ -1289,6 +1294,9 @@ nsresult nsEventListenerManager::HandleEvent(nsIPresContext* aPresContext,
                   case NS_MENU_CREATE:
                     ret = mMenuListener->Create(*aDOMEvent);
                     break;
+                  case NS_XUL_CLOSE:
+                    ret = mMenuListener->Close(*aDOMEvent);
+                    break;
                   case NS_MENU_DESTROY:
                     ret = mMenuListener->Destroy(*aDOMEvent);
                     break;
@@ -1316,6 +1324,12 @@ nsresult nsEventListenerManager::HandleEvent(nsIPresContext* aPresContext,
                       correctSubType = PR_TRUE;
                     }
                     break;
+                  case NS_XUL_CLOSE:
+                    subType = NS_EVENT_BITS_XUL_CLOSE;
+                    if (ls->mSubType & NS_EVENT_BITS_XUL_CLOSE) {
+                      correctSubType = PR_TRUE;
+                    }
+                    break;
                   case NS_MENU_DESTROY:
                     subType = NS_EVENT_BITS_MENU_DESTROY;
                     if (ls->mSubType & NS_EVENT_BITS_MENU_DESTROY) {
diff --git a/content/events/src/nsEventListenerManager.h b/content/events/src/nsEventListenerManager.h
index c47d9307fe1..c1773290be1 100644
--- a/content/events/src/nsEventListenerManager.h
+++ b/content/events/src/nsEventListenerManager.h
@@ -184,10 +184,11 @@ protected:
 //nsIDOMMenuListener
 #define NS_EVENT_BITS_MENU_NONE          0x00
 #define NS_EVENT_BITS_MENU_CREATE        0x01
-#define NS_EVENT_BITS_MENU_DESTROY       0x02
-#define NS_EVENT_BITS_MENU_ACTION        0x04
-#define NS_EVENT_BITS_XUL_BROADCAST      0x08
-#define NS_EVENT_BITS_XUL_COMMAND_UPDATE 0x10
+#define NS_EVENT_BITS_XUL_CLOSE          0x02
+#define NS_EVENT_BITS_MENU_DESTROY       0x04
+#define NS_EVENT_BITS_MENU_ACTION        0x08
+#define NS_EVENT_BITS_XUL_BROADCAST      0x10
+#define NS_EVENT_BITS_XUL_COMMAND_UPDATE 0x20
 
 //nsIDOMDragListener
 #define NS_EVENT_BITS_DRAG_NONE     0x00
diff --git a/content/shared/public/nsLayoutAtomList.h b/content/shared/public/nsLayoutAtomList.h
index c374090684f..110cfc6213e 100644
--- a/content/shared/public/nsLayoutAtomList.h
+++ b/content/shared/public/nsLayoutAtomList.h
@@ -117,6 +117,7 @@ LAYOUT_ATOM(onblur, "onblur")
 LAYOUT_ATOM(onbroadcast, "onbroadcast")
 LAYOUT_ATOM(onchange, "onchange")
 LAYOUT_ATOM(onclick, "onclick")
+LAYOUT_ATOM(onclose, "onclose")
 LAYOUT_ATOM(oncommand, "oncommand")
 LAYOUT_ATOM(oncommandupdate, "oncommandupdate")
 LAYOUT_ATOM(oncreate, "oncreate")
diff --git a/content/xul/templates/src/nsXULContentUtils.cpp b/content/xul/templates/src/nsXULContentUtils.cpp
index 4f484dab68e..f5353745c92 100644
--- a/content/xul/templates/src/nsXULContentUtils.cpp
+++ b/content/xul/templates/src/nsXULContentUtils.cpp
@@ -206,6 +206,7 @@ nsXULContentUtils::kEventHandlerMap[] = {
     { "onerror",         nsnull, &NS_GET_IID(nsIDOMLoadListener)        },
 
     { "oncreate",        nsnull, &NS_GET_IID(nsIDOMMenuListener)        },
+    { "onclose",         nsnull, &NS_GET_IID(nsIDOMMenuListener)        },
     { "ondestroy",       nsnull, &NS_GET_IID(nsIDOMMenuListener)        },
     { "oncommand",       nsnull, &NS_GET_IID(nsIDOMMenuListener)        },
     { "onbroadcast",     nsnull, &NS_GET_IID(nsIDOMMenuListener)        },
diff --git a/dom/public/coreEvents/nsIDOMMenuListener.h b/dom/public/coreEvents/nsIDOMMenuListener.h
index 3e24118821c..48ee1780ca4 100644
--- a/dom/public/coreEvents/nsIDOMMenuListener.h
+++ b/dom/public/coreEvents/nsIDOMMenuListener.h
@@ -37,6 +37,7 @@ public:
   NS_DEFINE_STATIC_IID_ACCESSOR(NS_IDOMMENULISTENER_IID)
 
   NS_IMETHOD Create(nsIDOMEvent* aEvent) = 0;
+  NS_IMETHOD Close(nsIDOMEvent* aEvent) = 0;
   NS_IMETHOD Destroy(nsIDOMEvent* aEvent) = 0;
   NS_IMETHOD Action(nsIDOMEvent* aEvent) = 0;
   NS_IMETHOD Broadcast(nsIDOMEvent* aEvent) = 0;
diff --git a/dom/src/base/nsGlobalWindow.cpp b/dom/src/base/nsGlobalWindow.cpp
index f3df82116f9..a4591af7452 100644
--- a/dom/src/base/nsGlobalWindow.cpp
+++ b/dom/src/base/nsGlobalWindow.cpp
@@ -2696,8 +2696,8 @@ GlobalWindowImpl::CheckForEventListener(JSContext *aContext, nsString& aPropName
       }
     }
   }
-  else if (aPropName == "onload" || aPropName == "onunload" || aPropName == "onabort" ||
-           aPropName == "onerror") {
+  else if (aPropName == "onload" || aPropName == "onunload" || aPropName == "onclose" ||
+           aPropName == "onabort" || aPropName == "onerror") {
     if (NS_OK == GetListenerManager(&mManager)) {
       nsIScriptContext *mScriptCX = (nsIScriptContext *)JS_GetContextPrivate(aContext);
       if (NS_OK != mManager->RegisterScriptEventListener(mScriptCX, this, atom, kIDOMLoadListenerIID)) {
diff --git a/layout/base/nsLayoutAtomList.h b/layout/base/nsLayoutAtomList.h
index c374090684f..110cfc6213e 100644
--- a/layout/base/nsLayoutAtomList.h
+++ b/layout/base/nsLayoutAtomList.h
@@ -117,6 +117,7 @@ LAYOUT_ATOM(onblur, "onblur")
 LAYOUT_ATOM(onbroadcast, "onbroadcast")
 LAYOUT_ATOM(onchange, "onchange")
 LAYOUT_ATOM(onclick, "onclick")
+LAYOUT_ATOM(onclose, "onclose")
 LAYOUT_ATOM(oncommand, "oncommand")
 LAYOUT_ATOM(oncommandupdate, "oncommandupdate")
 LAYOUT_ATOM(oncreate, "oncreate")
diff --git a/layout/base/public/nsLayoutAtomList.h b/layout/base/public/nsLayoutAtomList.h
index c374090684f..110cfc6213e 100644
--- a/layout/base/public/nsLayoutAtomList.h
+++ b/layout/base/public/nsLayoutAtomList.h
@@ -117,6 +117,7 @@ LAYOUT_ATOM(onblur, "onblur")
 LAYOUT_ATOM(onbroadcast, "onbroadcast")
 LAYOUT_ATOM(onchange, "onchange")
 LAYOUT_ATOM(onclick, "onclick")
+LAYOUT_ATOM(onclose, "onclose")
 LAYOUT_ATOM(oncommand, "oncommand")
 LAYOUT_ATOM(oncommandupdate, "oncommandupdate")
 LAYOUT_ATOM(oncreate, "oncreate")
diff --git a/layout/events/src/nsDOMEvent.cpp b/layout/events/src/nsDOMEvent.cpp
index 3984ef9654e..17949c60851 100644
--- a/layout/events/src/nsDOMEvent.cpp
+++ b/layout/events/src/nsDOMEvent.cpp
@@ -50,8 +50,8 @@ static char* mEventNames[] = {
   "mouseout", "mousemove", "keydown", "keyup", "keypress",
   "focus", "blur", "load", "unload", "abort", "error",
   "submit", "reset", "change", "select", "input", "paint" ,"text",
-  "create", "destroy", "command", "broadcast", "commandupdate", "dragenter", "dragover", "dragexit",
-  "dragdrop", "draggesture"
+  "create", "close", "destroy", "command", "broadcast", "commandupdate",
+  "dragenter", "dragover", "dragexit", "dragdrop", "draggesture"
 }; 
 
 nsDOMEvent::nsDOMEvent(nsIPresContext* aPresContext, nsEvent* aEvent) {
@@ -855,6 +855,8 @@ const char* nsDOMEvent::GetEventName(PRUint32 aEventType)
     return mEventNames[eDOMEvents_focus];
   case NS_BLUR_CONTENT:
     return mEventNames[eDOMEvents_blur];
+  case NS_XUL_CLOSE:
+    return mEventNames[eDOMEvents_close];
   case NS_PAGE_LOAD:
   case NS_IMAGE_LOAD:
     return mEventNames[eDOMEvents_load];
diff --git a/layout/events/src/nsDOMEvent.h b/layout/events/src/nsDOMEvent.h
index 1b564253cb8..decc8be1f40 100644
--- a/layout/events/src/nsDOMEvent.h
+++ b/layout/events/src/nsDOMEvent.h
@@ -70,8 +70,9 @@ public:
     eDOMEvents_select,
     eDOMEvents_input,
     eDOMEvents_paint,
-	  eDOMEvents_text,
+    eDOMEvents_text,
     eDOMEvents_create,
+    eDOMEvents_close,
     eDOMEvents_destroy,
     eDOMEvents_command,
     eDOMEvents_broadcast,
diff --git a/layout/events/src/nsEventListenerManager.cpp b/layout/events/src/nsEventListenerManager.cpp
index c96aa2f2608..d12ca2aa7b8 100644
--- a/layout/events/src/nsEventListenerManager.cpp
+++ b/layout/events/src/nsEventListenerManager.cpp
@@ -388,6 +388,10 @@ nsresult nsEventListenerManager::GetIdentifiersForType(nsIAtom* aType, nsIID& aI
     aIID = kIDOMMenuListenerIID; 
     *aFlags = NS_EVENT_BITS_MENU_CREATE;
   }
+  else if (aType == nsLayoutAtoms::onclose) {
+    aIID = kIDOMMenuListenerIID; 
+    *aFlags = NS_EVENT_BITS_XUL_CLOSE;
+  }
   else if (aType == nsLayoutAtoms::ondestroy) {
     aIID = kIDOMMenuListenerIID; 
     *aFlags = NS_EVENT_BITS_MENU_DESTROY;
@@ -1268,6 +1272,7 @@ nsresult nsEventListenerManager::HandleEvent(nsIPresContext* aPresContext,
       break;
 
     case NS_MENU_CREATE:
+    case NS_XUL_CLOSE:
     case NS_MENU_DESTROY:
     case NS_MENU_ACTION:
     case NS_XUL_BROADCAST:
@@ -1289,6 +1294,9 @@ nsresult nsEventListenerManager::HandleEvent(nsIPresContext* aPresContext,
                   case NS_MENU_CREATE:
                     ret = mMenuListener->Create(*aDOMEvent);
                     break;
+                  case NS_XUL_CLOSE:
+                    ret = mMenuListener->Close(*aDOMEvent);
+                    break;
                   case NS_MENU_DESTROY:
                     ret = mMenuListener->Destroy(*aDOMEvent);
                     break;
@@ -1316,6 +1324,12 @@ nsresult nsEventListenerManager::HandleEvent(nsIPresContext* aPresContext,
                       correctSubType = PR_TRUE;
                     }
                     break;
+                  case NS_XUL_CLOSE:
+                    subType = NS_EVENT_BITS_XUL_CLOSE;
+                    if (ls->mSubType & NS_EVENT_BITS_XUL_CLOSE) {
+                      correctSubType = PR_TRUE;
+                    }
+                    break;
                   case NS_MENU_DESTROY:
                     subType = NS_EVENT_BITS_MENU_DESTROY;
                     if (ls->mSubType & NS_EVENT_BITS_MENU_DESTROY) {
diff --git a/layout/events/src/nsEventListenerManager.h b/layout/events/src/nsEventListenerManager.h
index c47d9307fe1..c1773290be1 100644
--- a/layout/events/src/nsEventListenerManager.h
+++ b/layout/events/src/nsEventListenerManager.h
@@ -184,10 +184,11 @@ protected:
 //nsIDOMMenuListener
 #define NS_EVENT_BITS_MENU_NONE          0x00
 #define NS_EVENT_BITS_MENU_CREATE        0x01
-#define NS_EVENT_BITS_MENU_DESTROY       0x02
-#define NS_EVENT_BITS_MENU_ACTION        0x04
-#define NS_EVENT_BITS_XUL_BROADCAST      0x08
-#define NS_EVENT_BITS_XUL_COMMAND_UPDATE 0x10
+#define NS_EVENT_BITS_XUL_CLOSE          0x02
+#define NS_EVENT_BITS_MENU_DESTROY       0x04
+#define NS_EVENT_BITS_MENU_ACTION        0x08
+#define NS_EVENT_BITS_XUL_BROADCAST      0x10
+#define NS_EVENT_BITS_XUL_COMMAND_UPDATE 0x20
 
 //nsIDOMDragListener
 #define NS_EVENT_BITS_DRAG_NONE     0x00
diff --git a/rdf/content/src/nsXULContentUtils.cpp b/rdf/content/src/nsXULContentUtils.cpp
index 4f484dab68e..f5353745c92 100644
--- a/rdf/content/src/nsXULContentUtils.cpp
+++ b/rdf/content/src/nsXULContentUtils.cpp
@@ -206,6 +206,7 @@ nsXULContentUtils::kEventHandlerMap[] = {
     { "onerror",         nsnull, &NS_GET_IID(nsIDOMLoadListener)        },
 
     { "oncreate",        nsnull, &NS_GET_IID(nsIDOMMenuListener)        },
+    { "onclose",         nsnull, &NS_GET_IID(nsIDOMMenuListener)        },
     { "ondestroy",       nsnull, &NS_GET_IID(nsIDOMMenuListener)        },
     { "oncommand",       nsnull, &NS_GET_IID(nsIDOMMenuListener)        },
     { "onbroadcast",     nsnull, &NS_GET_IID(nsIDOMMenuListener)        },
diff --git a/widget/public/nsGUIEvent.h b/widget/public/nsGUIEvent.h
index 6f8d8dfa41c..b3c27cb5e46 100644
--- a/widget/public/nsGUIEvent.h
+++ b/widget/public/nsGUIEvent.h
@@ -244,18 +244,20 @@ enum nsDragDropEventStatus {
 
 // Widget is being created
 #define NS_CREATE                       (NS_WINDOW_START)
+// Widget may be destroyed
+#define NS_XUL_CLOSE                    (NS_WINDOW_START + 1)
 // Widget is being destroyed
-#define NS_DESTROY                      (NS_WINDOW_START + 1)
+#define NS_DESTROY                      (NS_WINDOW_START + 2)
 // Widget was resized
-#define NS_SIZE                         (NS_WINDOW_START + 2)
+#define NS_SIZE                         (NS_WINDOW_START + 3)
 // Widget gained focus
-#define NS_GOTFOCUS                     (NS_WINDOW_START + 3)
+#define NS_GOTFOCUS                     (NS_WINDOW_START + 4)
 // Widget lost focus
-#define NS_LOSTFOCUS                    (NS_WINDOW_START + 4)
+#define NS_LOSTFOCUS                    (NS_WINDOW_START + 5)
 // Widget got activated
-#define NS_ACTIVATE                     (NS_WINDOW_START + 5)
+#define NS_ACTIVATE                     (NS_WINDOW_START + 6)
 // Widget got deactivated
-#define NS_DEACTIVATE                   (NS_WINDOW_START + 6)
+#define NS_DEACTIVATE                   (NS_WINDOW_START + 7)
 // Widget needs to be repainted
 #define NS_PAINT                        (NS_WINDOW_START + 30)
 // Key is pressed within a window