--- a/toolkit/components/satchel/nsFormFillController.cpp
+++ b/toolkit/components/satchel/nsFormFillController.cpp
@@ -6,16 +6,17 @@
 
 #include "nsFormFillController.h"
 
 #include "mozilla/ClearOnShutdown.h"
 #include "mozilla/ErrorResult.h"
 #include "mozilla/dom/Element.h"
 #include "mozilla/dom/Event.h" // for nsIDOMEvent::InternalDOMEvent()
 #include "mozilla/dom/HTMLInputElement.h"
+#include "mozilla/Logging.h"
 #include "nsIFormAutoComplete.h"
 #include "nsIInputListAutoComplete.h"
 #include "nsIAutoCompleteSimpleResult.h"
 #include "nsString.h"
 #include "nsReadableUtils.h"
 #include "nsIServiceManager.h"
 #include "nsIInterfaceRequestor.h"
 #include "nsIInterfaceRequestorUtils.h"
@@ -41,16 +42,19 @@
 #include "nsILoadContext.h"
 #include "nsIFrame.h"
 #include "nsIScriptSecurityManager.h"
 #include "nsFocusManager.h"
 
 using namespace mozilla;
 using namespace mozilla::dom;
 using mozilla::ErrorResult;
+using mozilla::LogLevel;
+
+static mozilla::LazyLogModule sLogger("satchel");
 
 static nsIFormAutoComplete*
 GetFormAutoComplete()
 {
   static nsCOMPtr<nsIFormAutoComplete> sInstance;
   static bool sInitialized = false;
   if (!sInitialized) {
     nsresult rv;
@@ -229,16 +233,17 @@ nsFormFillController::NativeAnonymousChi
 void
 nsFormFillController::ParentChainChanged(nsIContent* aContent)
 {
 }
 
 void
 nsFormFillController::NodeWillBeDestroyed(const nsINode* aNode)
 {
+  MOZ_LOG(sLogger, LogLevel::Verbose, ("NodeWillBeDestroyed: %p", aNode));
   mPwmgrInputs.Remove(aNode);
   mAutofillInputs.Remove(aNode);
   if (aNode == mListNode) {
     mListNode = nullptr;
     RevalidateDataList();
   } else if (aNode == mFocusedInputNode) {
     mFocusedInputNode = nullptr;
     mFocusedInput = nullptr;
@@ -256,16 +261,18 @@ nsFormFillController::MaybeRemoveMutatio
 }
 
 ////////////////////////////////////////////////////////////////////////
 //// nsIFormFillController
 
 NS_IMETHODIMP
 nsFormFillController::AttachToBrowser(nsIDocShell *aDocShell, nsIAutoCompletePopup *aPopup)
 {
+  MOZ_LOG(sLogger, LogLevel::Debug,
+          ("AttachToBrowser for docShell %p with popup %p", aDocShell, aPopup));
   NS_ENSURE_TRUE(aDocShell && aPopup, NS_ERROR_ILLEGAL_VALUE);
 
   mDocShells.AppendElement(aDocShell);
   mPopups.AppendElement(aPopup);
 
   // Listen for focus events on the domWindow of the docShell
   nsCOMPtr<nsPIDOMWindowOuter> window = GetWindowForDocShell(aDocShell);
   AddWindowListeners(window);
@@ -335,16 +342,19 @@ nsFormFillController::MarkAsAutofillFiel
 {
   /*
    * Support other components implementing form autofill and handle autocomplete
    * for the field.
    */
   nsCOMPtr<nsINode> node = do_QueryInterface(aInput);
   NS_ENSURE_STATE(node);
 
+  MOZ_LOG(sLogger, LogLevel::Verbose,
+          ("MarkAsAutofillField: aInput = %p, node = %p", aInput, node.get()));
+
   if (mAutofillInputs.Get(node)) {
     return NS_OK;
   }
 
   mAutofillInputs.Put(node, true);
   node->AddMutationObserverUnlessExists(this);
 
   nsCOMPtr<nsITextControlElement> txtCtrl = do_QueryInterface(aInput);
@@ -581,23 +591,25 @@ nsFormFillController::GetSearchCount(uin
   *aSearchCount = 1;
   return NS_OK;
 }
 
 NS_IMETHODIMP
 nsFormFillController::GetSearchAt(uint32_t index, nsACString & _retval)
 {
   if (mAutofillInputs.Get(mFocusedInputNode)) {
+    MOZ_LOG(sLogger, LogLevel::Debug, ("GetSearchAt: autofill-profiles field"));
     nsCOMPtr<nsIAutoCompleteSearch> profileSearch = do_GetService("@mozilla.org/autocomplete/search;1?name=autofill-profiles");
     if (profileSearch) {
       _retval.AssignLiteral("autofill-profiles");
       return NS_OK;
     }
   }
 
+  MOZ_LOG(sLogger, LogLevel::Debug, ("GetSearchAt: form-history field"));
   _retval.AssignLiteral("form-history");
   return NS_OK;
 }
 
 NS_IMETHODIMP
 nsFormFillController::GetTextValue(nsAString & aTextValue)
 {
   if (mFocusedInput) {
@@ -757,25 +769,28 @@ nsFormFillController::GetUserContextId(u
 
 ////////////////////////////////////////////////////////////////////////
 //// nsIAutoCompleteSearch
 
 NS_IMETHODIMP
 nsFormFillController::StartSearch(const nsAString &aSearchString, const nsAString &aSearchParam,
                                   nsIAutoCompleteResult *aPreviousResult, nsIAutoCompleteObserver *aListener)
 {
+  MOZ_LOG(sLogger, LogLevel::Debug, ("StartSearch for %p", mFocusedInput));
+
   nsresult rv;
   nsCOMPtr<nsIFormControl> formControl = do_QueryInterface(mFocusedInputNode);
 
   // If the login manager has indicated it's responsible for this field, let it
   // handle the autocomplete. Otherwise, handle with form history.
   // This method is sometimes called in unit tests and from XUL without a focused node.
   if (mFocusedInputNode &&
       (mPwmgrInputs.Get(mFocusedInputNode) ||
        formControl->ControlType() == NS_FORM_INPUT_PASSWORD)) {
+    MOZ_LOG(sLogger, LogLevel::Debug, ("StartSearch: login field"));
 
     // Handle the case where a password field is focused but
     // MarkAsLoginManagerField wasn't called because password manager is disabled.
     if (!mLoginManager) {
       mLoginManager = do_GetService("@mozilla.org/login-manager;1");
     }
 
     if (NS_WARN_IF(!mLoginManager)) {
@@ -786,16 +801,17 @@ nsFormFillController::StartSearch(const 
     // satchel manage the field?
     mLastListener = aListener;
     rv = mLoginManager->AutoCompleteSearchAsync(aSearchString,
                                                 aPreviousResult,
                                                 mFocusedInput,
                                                 this);
     NS_ENSURE_SUCCESS(rv, rv);
   } else {
+    MOZ_LOG(sLogger, LogLevel::Debug, ("StartSearch: non-login field"));
     mLastListener = aListener;
 
     nsCOMPtr<nsIAutoCompleteResult> datalistResult;
     if (mFocusedInput) {
       rv = PerformInputListAutoComplete(aSearchString,
                                         getter_AddRefs(datalistResult));
       NS_ENSURE_SUCCESS(rv, rv);
     }
@@ -1011,16 +1027,17 @@ nsFormFillController::IsTextControl(nsIN
   nsCOMPtr<nsIFormControl> formControl = do_QueryInterface(aNode);
   return formControl &&
          formControl->IsSingleLineTextControl(false);
 }
 
 void
 nsFormFillController::MaybeStartControllingInput(nsIDOMHTMLInputElement* aInput)
 {
+  MOZ_LOG(sLogger, LogLevel::Verbose, ("MaybeStartControllingInput for %p", aInput));
   nsCOMPtr<nsINode> inputNode = do_QueryInterface(aInput);
   if (!inputNode) {
     return;
   }
 
   if (!IsTextControl(inputNode)) {
     return;
   }
@@ -1273,16 +1290,17 @@ nsFormFillController::ShowPopup()
 }
 
 ////////////////////////////////////////////////////////////////////////
 //// nsFormFillController
 
 void
 nsFormFillController::AddWindowListeners(nsPIDOMWindowOuter* aWindow)
 {
+  MOZ_LOG(sLogger, LogLevel::Debug, ("AddWindowListeners for window %p", aWindow));
   if (!aWindow) {
     return;
   }
 
   EventTarget* target = aWindow->GetChromeEventHandler();
 
   if (!target) {
     return;
@@ -1308,16 +1326,17 @@ nsFormFillController::AddWindowListeners
 
   // Note that any additional listeners added should ensure that they ignore
   // untrusted events, which might be sent by content that's up to no good.
 }
 
 void
 nsFormFillController::RemoveWindowListeners(nsPIDOMWindowOuter* aWindow)
 {
+  MOZ_LOG(sLogger, LogLevel::Debug, ("RemoveWindowListeners for window %p", aWindow));
   if (!aWindow) {
     return;
   }
 
   StopControllingInput();
 
   nsCOMPtr<nsIDocument> doc = aWindow->GetDoc();
   RemoveForDocument(doc);
@@ -1339,16 +1358,17 @@ nsFormFillController::RemoveWindowListen
   target->RemoveEventListener(NS_LITERAL_STRING("compositionend"), this,
                               true);
   target->RemoveEventListener(NS_LITERAL_STRING("contextmenu"), this, true);
 }
 
 void
 nsFormFillController::StartControllingInput(nsIDOMHTMLInputElement *aInput)
 {
+  MOZ_LOG(sLogger, LogLevel::Verbose, ("StartControllingInput for %p", aInput));
   // Make sure we're not still attached to an input
   StopControllingInput();
 
   if (!mController) {
     return;
   }
 
   // Find the currently focused docShell
@@ -1391,20 +1411,24 @@ nsFormFillController::StopControllingInp
 
   if (mController) {
     // 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
     nsCOMPtr<nsIAutoCompleteInput> input;
     mController->GetInput(getter_AddRefs(input));
     if (input == this) {
+      MOZ_LOG(sLogger, LogLevel::Verbose,
+              ("StopControllingInput: Nulled controller input for %p", this));
       mController->SetInput(nullptr);
     }
   }
 
+  MOZ_LOG(sLogger, LogLevel::Verbose,
+          ("StopControllingInput: Stopped controlling %p", mFocusedInput));
   if (mFocusedInputNode) {
     MaybeRemoveMutationObserver(mFocusedInputNode);
 
     mFocusedInputNode = nullptr;
     mFocusedInput = nullptr;
   }
 
   if (mFocusedPopup) {