diff --git a/toolkit/components/autocomplete/public/nsIAutoCompleteSearch.idl b/toolkit/components/autocomplete/public/nsIAutoCompleteSearch.idl
index cbf34c7609ba..4b09c6527d2b 100644
--- a/toolkit/components/autocomplete/public/nsIAutoCompleteSearch.idl
+++ b/toolkit/components/autocomplete/public/nsIAutoCompleteSearch.idl
@@ -63,7 +63,7 @@ interface nsIAutoCompleteSearch : nsISupports
   void stopSearch();
 };
 
-[scriptable, uuid(18C36504-9A4C-4ac3-8494-BD05E00AE27F)]
+[scriptable, uuid(8bd1dbbc-dcce-4007-9afa-b551eb687b61)]
 interface nsIAutoCompleteObserver : nsISupports
 { 
   /*
@@ -73,4 +73,12 @@ interface nsIAutoCompleteObserver : nsISupports
    * @param result - The search result object
    */
   void onSearchResult(in nsIAutoCompleteSearch search, in nsIAutoCompleteResult result);
+
+  /*
+   * Called to update with new results
+   *
+   * @param search - The search object that processed this search
+   * @param result - The search result object
+   */
+  void onUpdateSearchResult(in nsIAutoCompleteSearch search, in nsIAutoCompleteResult result);
 };
diff --git a/toolkit/components/autocomplete/src/nsAutoCompleteController.cpp b/toolkit/components/autocomplete/src/nsAutoCompleteController.cpp
index 300174be0a55..c0b94d2407a0 100644
--- a/toolkit/components/autocomplete/src/nsAutoCompleteController.cpp
+++ b/toolkit/components/autocomplete/src/nsAutoCompleteController.cpp
@@ -691,6 +691,13 @@ nsAutoCompleteController::GetSearchString(nsAString &aSearchString)
 ////////////////////////////////////////////////////////////////////////
 //// nsIAutoCompleteObserver
 
+NS_IMETHODIMP
+nsAutoCompleteController::OnUpdateSearchResult(nsIAutoCompleteSearch *aSearch, nsIAutoCompleteResult* aResult)
+{
+  ClearResults();
+  return OnSearchResult(aSearch, aResult);
+}
+
 NS_IMETHODIMP
 nsAutoCompleteController::OnSearchResult(nsIAutoCompleteSearch *aSearch, nsIAutoCompleteResult* aResult)
 {
diff --git a/toolkit/components/satchel/src/nsFormFillController.cpp b/toolkit/components/satchel/src/nsFormFillController.cpp
index f5882974c045..5cb5b035c408 100644
--- a/toolkit/components/satchel/src/nsFormFillController.cpp
+++ b/toolkit/components/satchel/src/nsFormFillController.cpp
@@ -72,6 +72,7 @@
 #include "nsEmbedCID.h"
 #include "nsIDOMNSEditableElement.h"
 #include "nsIDOMNSEvent.h"
+#include "mozilla/dom/Element.h"
 
 NS_INTERFACE_MAP_BEGIN(nsFormFillController)
   NS_INTERFACE_MAP_ENTRY(nsIFormFillController)
@@ -83,6 +84,7 @@ NS_INTERFACE_MAP_BEGIN(nsFormFillController)
   NS_INTERFACE_MAP_ENTRY(nsIDOMMouseListener)
   NS_INTERFACE_MAP_ENTRY(nsIDOMCompositionListener)
   NS_INTERFACE_MAP_ENTRY(nsIDOMContextMenuListener)
+  NS_INTERFACE_MAP_ENTRY(nsIMutationObserver)
   NS_INTERFACE_MAP_ENTRY_AMBIGUOUS(nsISupports, nsIFormFillController)
   NS_INTERFACE_MAP_ENTRY_AMBIGUOUS(nsIDOMEventListener, nsIDOMFocusListener)
 NS_INTERFACE_MAP_END
@@ -119,6 +121,79 @@ nsFormFillController::~nsFormFillController()
   }
 }
 
+////////////////////////////////////////////////////////////////////////
+//// nsIMutationObserver
+//
+
+void
+nsFormFillController::AttributeChanged(nsIDocument* aDocument,
+                                       mozilla::dom::Element* aElement,
+                                       PRInt32 aNameSpaceID,
+                                       nsIAtom* aAttribute, PRInt32 aModType)
+{
+  RevalidateDataList();
+}
+
+void
+nsFormFillController::ContentAppended(nsIDocument* aDocument,
+                                      nsIContent* aContainer,
+                                      nsIContent* aChild,
+                                      PRInt32 aIndexInContainer)
+{
+  RevalidateDataList();
+}
+
+void
+nsFormFillController::ContentInserted(nsIDocument* aDocument,
+                                      nsIContent* aContainer,
+                                      nsIContent* aChild,
+                                      PRInt32 aIndexInContainer)
+{
+  RevalidateDataList();
+}
+
+void
+nsFormFillController::ContentRemoved(nsIDocument* aDocument,
+                                     nsIContent* aContainer,
+                                     nsIContent* aChild,
+                                     PRInt32 aIndexInContainer,
+                                     nsIContent* aPreviousSibling)
+{
+  RevalidateDataList();
+}
+
+void
+nsFormFillController::CharacterDataWillChange(nsIDocument* aDocument,
+                                              nsIContent* aContent,
+                                              CharacterDataChangeInfo* aInfo)
+{
+}
+
+void
+nsFormFillController::CharacterDataChanged(nsIDocument* aDocument,
+                                           nsIContent* aContent,
+                                           CharacterDataChangeInfo* aInfo)
+{
+}
+
+void
+nsFormFillController::AttributeWillChange(nsIDocument* aDocument,
+                                          mozilla::dom::Element* aElement,
+                                          PRInt32 aNameSpaceID,
+                                          nsIAtom* aAttribute, PRInt32 aModType)
+{
+}
+
+void
+nsFormFillController::ParentChainChanged(nsIContent* aContent)
+{
+}
+
+void
+nsFormFillController::NodeWillBeDestroyed(const nsINode* aNode)
+{
+}
+
 ////////////////////////////////////////////////////////////////////////
 //// nsIFormFillController
 
@@ -526,6 +601,10 @@ nsFormFillController::StartSearch(const nsAString &aSearchString, const nsAStrin
       NS_ENSURE_SUCCESS(rv, rv);
     }
 
+    mLastSearchResult = formHistoryResult;
+    mLastListener = aListener;
+    mLastSearchString = aSearchString;
+
     nsCOMPtr <nsIInputListAutoComplete> inputListAutoComplete =
       do_GetService("@mozilla.org/satchel/inputlist-autocomplete;1", &rv);
     NS_ENSURE_SUCCESS(rv, rv);
@@ -534,6 +613,16 @@ nsFormFillController::StartSearch(const nsAString &aSearchString, const nsAStrin
                                                    aSearchString,
                                                    mFocusedInput,
                                                    getter_AddRefs(result));
+
+    if (mFocusedInput) {
+      nsCOMPtr<nsIDOMHTMLElement> list;
+      mFocusedInput->GetList(getter_AddRefs(list));
+
+      nsCOMPtr<nsINode> node = do_QueryInterface(list);
+      if(node) {
+        node->AddMutationObserverUnlessExists(this);
+      }
+    }
   }
   NS_ENSURE_SUCCESS(rv, rv);
 
@@ -542,6 +631,21 @@ nsFormFillController::StartSearch(const nsAString &aSearchString, const nsAStrin
   return NS_OK;
 }
 
+void nsFormFillController::RevalidateDataList()
+{
+  nsresult rv;
+  nsCOMPtr <nsIInputListAutoComplete> inputListAutoComplete =
+    do_GetService("@mozilla.org/satchel/inputlist-autocomplete;1", &rv);
+
+  nsCOMPtr<nsIAutoCompleteResult> result;
+
+  rv = inputListAutoComplete->AutoCompleteSearch(mLastSearchResult,
+                                                 mLastSearchString,
+                                                 mFocusedInput,
+                                                 getter_AddRefs(result));
+  mLastListener->OnUpdateSearchResult(this, result);
+}
+
 NS_IMETHODIMP
 nsFormFillController::StopSearch()
 {
@@ -1156,6 +1260,16 @@ nsFormFillController::StopControllingInput()
 {
   RemoveKeyListener();
 
+  if(mFocusedInput) {
+    nsCOMPtr<nsIDOMHTMLElement> list;
+    mFocusedInput->GetList(getter_AddRefs(list));
+
+    nsCOMPtr<nsINode> node = do_QueryInterface(list);
+    if (node) {
+      node->RemoveMutationObserver(this);
+    }
+  }
+
   // Reset the controller's input, but not if it has been switched
   // to another input already, which might happen if the user switches
   // focus by clicking another autocomplete textbox
diff --git a/toolkit/components/satchel/src/nsFormFillController.h b/toolkit/components/satchel/src/nsFormFillController.h
index e98281d26fea..48af7a30442d 100644
--- a/toolkit/components/satchel/src/nsFormFillController.h
+++ b/toolkit/components/satchel/src/nsFormFillController.h
@@ -58,6 +58,7 @@
 #include "nsIDOMWindow.h"
 #include "nsIDOMHTMLInputElement.h"
 #include "nsILoginManager.h"
+#include "nsIMutationObserver.h"
 
 class nsFormHistory;
 
@@ -69,7 +70,8 @@ class nsFormFillController : public nsIFormFillController,
                              public nsIDOMCompositionListener,
                              public nsIDOMFormListener,
                              public nsIDOMMouseListener,
-                             public nsIDOMContextMenuListener
+                             public nsIDOMContextMenuListener,
+                             public nsIMutationObserver
 {
 public:
   NS_DECL_ISUPPORTS
@@ -77,6 +79,7 @@ public:
   NS_DECL_NSIAUTOCOMPLETESEARCH
   NS_DECL_NSIAUTOCOMPLETEINPUT
   NS_DECL_NSIDOMEVENTLISTENER
+  NS_DECL_NSIMUTATIONOBSERVER
 
   // nsIDOMFocusListener
   NS_IMETHOD Focus(nsIDOMEvent* aEvent);
@@ -122,6 +125,7 @@ protected:
   void StartControllingInput(nsIDOMHTMLInputElement *aInput);
   void StopControllingInput();
   
+  void RevalidateDataList();
   PRBool RowMatch(nsFormHistory *aHistory, PRUint32 aIndex, const nsAString &aInputName, const nsAString &aInputValue);
   
   inline nsIDocShell *GetDocShellForInput(nsIDOMHTMLInputElement *aInput);
@@ -143,6 +147,11 @@ protected:
   nsCOMPtr<nsISupportsArray> mDocShells;
   nsCOMPtr<nsISupportsArray> mPopups;
 
+  //these are used to dynamically update the autocomplete
+  nsCOMPtr<nsIAutoCompleteResult> mLastSearchResult;
+  nsCOMPtr<nsIAutoCompleteObserver> mLastListener;
+  nsString mLastSearchString;
+
   nsDataHashtable<nsISupportsHashKey,PRInt32> mPwmgrInputs;
 
   PRUint32 mTimeout;