diff --git a/mozilla/toolkit/components/autocomplete/public/nsIAutoCompleteInput.idl b/mozilla/toolkit/components/autocomplete/public/nsIAutoCompleteInput.idl
index f27728fbab9..4db837efa44 100644
--- a/mozilla/toolkit/components/autocomplete/public/nsIAutoCompleteInput.idl
+++ b/mozilla/toolkit/components/autocomplete/public/nsIAutoCompleteInput.idl
@@ -157,3 +157,13 @@ interface nsIAutoCompleteInput : nsISupports
    */
   boolean onTextReverted();
 };
+
+[scriptable, uuid(CCD37136-76E8-47a7-B46C-B8FEE8EB0536)]
+interface nsIAutoCompleteInput_MOZILLA_1_8_BRANCH : nsIAutoCompleteInput
+{
+  /*
+   * This popup should consume or dispatch the rollup event.
+   * TRUE: should consume; FALSE: should dispatch.
+   */
+  readonly attribute boolean consumeRollupEvent;
+};
diff --git a/mozilla/toolkit/components/autocomplete/src/nsAutoCompleteController.cpp b/mozilla/toolkit/components/autocomplete/src/nsAutoCompleteController.cpp
index 7edac00f304..a4580ec63a3 100644
--- a/mozilla/toolkit/components/autocomplete/src/nsAutoCompleteController.cpp
+++ b/mozilla/toolkit/components/autocomplete/src/nsAutoCompleteController.cpp
@@ -589,8 +589,14 @@ nsAutoCompleteController::AttachRollupListener()
 {
   nsIWidget* widget = GetPopupWidget();
   NS_ENSURE_TRUE(widget, NS_ERROR_FAILURE);
+  NS_ASSERTION(mInput, "mInput must not be null.");
+  PRBool consumeRollupEvent = PR_FALSE;
+  nsCOMPtr<nsIAutoCompleteInput_MOZILLA_1_8_BRANCH> input =
+    do_QueryInterface(mInput);
+  NS_ASSERTION(input, "mInput must have nsIAutoCompleteInput_MOZILLA_1_8_BRANCH interface.");
+  input->GetConsumeRollupEvent(&consumeRollupEvent);
   return widget->CaptureRollupEvents((nsIRollupListener*)this,
-                                     PR_TRUE, PR_FALSE);
+                                     PR_TRUE, consumeRollupEvent);
 }
 
 NS_IMETHODIMP
diff --git a/mozilla/toolkit/components/satchel/src/nsFormFillController.cpp b/mozilla/toolkit/components/satchel/src/nsFormFillController.cpp
index d1418819547..2dc634caecd 100644
--- a/mozilla/toolkit/components/satchel/src/nsFormFillController.cpp
+++ b/mozilla/toolkit/components/satchel/src/nsFormFillController.cpp
@@ -80,6 +80,7 @@
 NS_INTERFACE_MAP_BEGIN(nsFormFillController)
   NS_INTERFACE_MAP_ENTRY(nsIFormFillController)
   NS_INTERFACE_MAP_ENTRY(nsIAutoCompleteInput)
+  NS_INTERFACE_MAP_ENTRY(nsIAutoCompleteInput_MOZILLA_1_8_BRANCH)
   NS_INTERFACE_MAP_ENTRY(nsIAutoCompleteSearch)
   NS_INTERFACE_MAP_ENTRY(nsIDOMFocusListener)
   NS_INTERFACE_MAP_ENTRY(nsIDOMKeyListener)
@@ -482,6 +483,16 @@ nsFormFillController::OnTextReverted(PRBool *_retval)
   return NS_OK;
 }
 
+////////////////////////////////////////////////////////////////////////
+//// nsIAutoCompleteInput_MOZILLA_1_8_BRANCH
+
+NS_IMETHODIMP
+nsFormFillController::GetConsumeRollupEvent(PRBool *aConsumeRollupEvent)
+{
+  *aConsumeRollupEvent = PR_FALSE;
+  return NS_OK;
+}
+
 ////////////////////////////////////////////////////////////////////////
 //// nsIAutoCompleteSearch
 
diff --git a/mozilla/toolkit/components/satchel/src/nsFormFillController.h b/mozilla/toolkit/components/satchel/src/nsFormFillController.h
index 7538c58702d..345480050ff 100644
--- a/mozilla/toolkit/components/satchel/src/nsFormFillController.h
+++ b/mozilla/toolkit/components/satchel/src/nsFormFillController.h
@@ -60,7 +60,7 @@
 class nsFormHistory;
 
 class nsFormFillController : public nsIFormFillController,
-                             public nsIAutoCompleteInput,
+                             public nsIAutoCompleteInput_MOZILLA_1_8_BRANCH,
                              public nsIAutoCompleteSearch,
                              public nsIDOMFocusListener,
                              public nsIDOMKeyListener,
@@ -74,6 +74,7 @@ public:
   NS_DECL_NSIFORMFILLCONTROLLER
   NS_DECL_NSIAUTOCOMPLETESEARCH
   NS_DECL_NSIAUTOCOMPLETEINPUT
+  NS_DECL_NSIAUTOCOMPLETEINPUT_MOZILLA_1_8_BRANCH
   NS_DECL_NSIDOMEVENTLISTENER
 
   // nsIDOMFocusListener
diff --git a/mozilla/toolkit/content/widgets/autocomplete.xml b/mozilla/toolkit/content/widgets/autocomplete.xml
index c77b5891d60..82bb9bd073f 100644
--- a/mozilla/toolkit/content/widgets/autocomplete.xml
+++ b/mozilla/toolkit/content/widgets/autocomplete.xml
@@ -74,7 +74,9 @@
       <xul:popupset anonid="popupset" class="autocomplete-result-popupset"/>
     </content>
 
-    <implementation implements="nsIAccessibleProvider, nsIAutoCompleteInput, nsIDOMXULMenuListElement">
+    <implementation implements="nsIAccessibleProvider,
+                                nsIAutoCompleteInput_MOZILLA_1_8_BRANCH,
+                                nsIDOMXULMenuListElement">
       <field name="mController">null</field>
       <field name="mSearchNames">null</field>
       <field name="mIgnoreInput">false</field>
@@ -164,7 +166,10 @@
 
       <property name="searchCount" readonly="true"
                 onget="this.initSearchNames(); return this.mSearchNames.length;"/>
-    
+
+      <property name="consumeRollupEvent" readonly="true"
+                onget="return true;"/>
+
       <method name="getSearchAt">
         <parameter name="aIndex"/>
         <body><![CDATA[