--- a/browser/base/content/test/urlbar/browser_urlbarSearchSuggestions_opt-out.js
+++ b/browser/base/content/test/urlbar/browser_urlbarSearchSuggestions_opt-out.js
@@ -57,16 +57,32 @@ add_task(async function focus() {
   // Check the Change Options link.
   let changeOptionsLink = document.getElementById("search-suggestions-change-settings");
   let prefsPromise = BrowserTestUtils.waitForLocationChange(gBrowser, "about:preferences#general-search");
   changeOptionsLink.click();
   await prefsPromise;
   Assert.ok(!gURLBar.popup.popupOpen, "popup should be closed");
 });
 
+add_task(async function new_tab() {
+  // Opening a new tab when the urlbar is unfocused, should focusing it and thus
+  // open the popup in order to show the notification.
+  setupVisibleHint();
+  gURLBar.blur();
+  let popupPromise = promisePopupShown(gURLBar.popup);
+  // openNewForegroundTab doesn't focus the urlbar.
+  await BrowserTestUtils.synthesizeKey("t", { accelKey: true }, gBrowser.selectedBrowser);
+  await popupPromise;
+  Assert.ok(gURLBar.popup.popupOpen, "popup should be open");
+  assertVisible(true);
+  assertFooterVisible(false);
+  Assert.equal(gURLBar.popup._matchCount, 0, "popup should have no results");
+  await BrowserTestUtils.removeTab(gBrowser.selectedTab);
+  Assert.ok(!gURLBar.popup.popupOpen, "popup should be closed");
+});
 
 add_task(async function privateWindow() {
   // Since suggestions are disabled in private windows, the notification should
   // not appear even when suggestions are otherwise enabled.
   setupVisibleHint();
   let win = await BrowserTestUtils.openNewBrowserWindow({ private: true });
   await promiseAutocompleteResultPopup("foo", win);
   assertVisible(false, win);

--- a/browser/base/content/urlbarBindings.xml
+++ b/browser/base/content/urlbarBindings.xml
@@ -1149,18 +1149,17 @@ file, You can obtain one at http://mozil
               }
               this.setAttribute("textoverflow", "true");
               break;
             case "underflow":
               this.removeAttribute("textoverflow");
               this._hideURLTooltip();
               break;
             case "TabSelect":
-              this.detachController();
-              this.attachController();
+              this.controller.resetInternalState();
               break;
           }
         ]]></body>
       </method>
 
       <!--
         onBeforeTextValueSet is called by the base-binding's .textValue getter.
         It should return the value that the getter should use.

--- a/toolkit/components/autocomplete/nsAutoCompleteController.cpp
+++ b/toolkit/components/autocomplete/nsAutoCompleteController.cpp
@@ -15,19 +15,22 @@
 #include "nsUnicharUtils.h"
 #include "nsIScriptSecurityManager.h"
 #include "nsITreeBoxObject.h"
 #include "nsITreeColumns.h"
 #include "nsIObserverService.h"
 #include "nsIDOMKeyEvent.h"
 #include "mozilla/Services.h"
 #include "mozilla/ModuleUtils.h"
+#include "mozilla/Unused.h"
 
 static const char *kAutoCompleteSearchCID = "@mozilla.org/autocomplete/search;1?name=";
 
+using namespace mozilla;
+
 namespace {
 
 void
 SetTextValue(nsIAutoCompleteInput* aInput,
              const nsString& aValue,
              uint16_t aReason) {
   nsresult rv = aInput->SetTextValueWithReason(aValue, aReason);
   if (NS_FAILED(rv)) {
@@ -125,63 +128,52 @@ nsAutoCompleteController::SetInitiallySe
 
 NS_IMETHODIMP
 nsAutoCompleteController::SetInput(nsIAutoCompleteInput *aInput)
 {
   // Don't do anything if the input isn't changing.
   if (mInput == aInput)
     return NS_OK;
 
-  // Clear out the current search context
+  Unused << ResetInternalState();
   if (mInput) {
-    // Stop all searches in case they are async.
-    StopSearch();
-    ClearResults();
+    mSearches.Clear();
     ClosePopup();
-    mSearches.Clear();
   }
 
   mInput = aInput;
 
   // Nothing more to do if the input was just being set to null.
-  if (!aInput)
+  if (!mInput) {
     return NS_OK;
+  }
+  nsCOMPtr<nsIAutoCompleteInput> input(mInput);
 
-  nsAutoString newValue;
-  aInput->GetTextValue(newValue);
+  // Reset the current search string.
+  input->GetTextValue(mSearchString);
 
   // Clear out this reference in case the new input's popup has no tree
   mTree = nullptr;
 
-  // Reset all search state members to default values
-  mSearchString = newValue;
-  mPlaceholderCompletionString.Truncate();
-  mDefaultIndexCompleted = false;
-  mProhibitAutoFill = false;
-  mSearchStatus = nsIAutoCompleteController::STATUS_NONE;
-  mRowCount = 0;
-  mSearchesOngoing = 0;
-  mCompletedSelectionIndex = -1;
-
   // Initialize our list of search objects
   uint32_t searchCount;
-  aInput->GetSearchCount(&searchCount);
+  input->GetSearchCount(&searchCount);
   mResults.SetCapacity(searchCount);
   mSearches.SetCapacity(searchCount);
   mImmediateSearchesCount = 0;
 
   const char *searchCID = kAutoCompleteSearchCID;
 
   // Since the controller can be used as a service it's important to reset this.
   mClearingAutoFillSearchesAgain = false;
 
   for (uint32_t i = 0; i < searchCount; ++i) {
     // Use the search name to create the contract id string for the search service
     nsAutoCString searchName;
-    aInput->GetSearchAt(i, searchName);
+    input->GetSearchAt(i, searchName);
     nsAutoCString cid(searchCID);
     cid.Append(searchName);
 
     // Use the created cid to get a pointer to the search service and store it for later
     nsCOMPtr<nsIAutoCompleteSearch> search = do_GetService(cid.get());
     if (search) {
       mSearches.AppendObject(search);
 
@@ -201,16 +193,39 @@ nsAutoCompleteController::SetInput(nsIAu
       }
     }
   }
 
   return NS_OK;
 }
 
 NS_IMETHODIMP
+nsAutoCompleteController::ResetInternalState()
+{
+  // Clear out the current search context
+  if (mInput) {
+    nsAutoString value;
+    mInput->GetTextValue(value);
+    // Stop all searches in case they are async.
+    Unused << StopSearch();
+    Unused << ClearResults();
+    mSearchString = value;
+  }
+
+  mPlaceholderCompletionString.Truncate();
+  mDefaultIndexCompleted = false;
+  mProhibitAutoFill = false;
+  mSearchStatus = nsIAutoCompleteController::STATUS_NONE;
+  mRowCount = 0;
+  mCompletedSelectionIndex = -1;
+
+  return NS_OK;
+}
+
+NS_IMETHODIMP
 nsAutoCompleteController::StartSearch(const nsAString &aSearchString)
 {
   mSearchString = aSearchString;
   StartSearches();
   return NS_OK;
 }
 
 NS_IMETHODIMP
@@ -1538,18 +1553,17 @@ nsAutoCompleteController::EnterMatch(boo
             result->GetFinalCompleteValueAt(defaultIndex, value);
             break;
           }
         }
       }
     }
   }
 
-  nsCOMPtr<nsIObserverService> obsSvc =
-    mozilla::services::GetObserverService();
+  nsCOMPtr<nsIObserverService> obsSvc = services::GetObserverService();
   NS_ENSURE_STATE(obsSvc);
   obsSvc->NotifyObservers(input, "autocomplete-will-enter-text", nullptr);
 
   if (!value.IsEmpty()) {
     SetTextValue(input, value, nsIAutoCompleteInput::TEXTVALUE_REASON_ENTERMATCH);
     input->SelectTextRange(value.Length(), value.Length());
     mSearchString = value;
   }
@@ -1574,18 +1588,17 @@ nsAutoCompleteController::RevertTextValu
 
   nsAutoString oldValue(mSearchString);
   nsCOMPtr<nsIAutoCompleteInput> input(mInput);
 
   bool cancel = false;
   input->OnTextReverted(&cancel);
 
   if (!cancel) {
-    nsCOMPtr<nsIObserverService> obsSvc =
-      mozilla::services::GetObserverService();
+    nsCOMPtr<nsIObserverService> obsSvc = services::GetObserverService();
     NS_ENSURE_STATE(obsSvc);
     obsSvc->NotifyObservers(input, "autocomplete-will-revert-text", nullptr);
 
     nsAutoString inputValue;
     input->GetTextValue(inputValue);
     // Don't change the value if it is the same to prevent sending useless events.
     // NOTE: how can |RevertTextValue| be called with inputValue != oldValue?
     if (!oldValue.Equals(inputValue)) {

--- a/toolkit/components/autocomplete/nsIAutoCompleteController.idl
+++ b/toolkit/components/autocomplete/nsIAutoCompleteController.idl
@@ -165,9 +165,16 @@ interface nsIAutoCompleteController : ns
    * This should be used when a search wants to pre-select an element before
    * the user starts using results.
    *
    * @note Setting this is not the same as just setting selectedIndex in
    * nsIAutocompletePopup, since this will take care of updating any internal
    * tracking variables of features like completeSelectedIndex.
    */
   void setInitiallySelectedIndex(in long index);
+
+  /*
+   * Reset controller internal caches for cases where the input doesn't change
+   * but its context resets, thus it is about to start a completely new search
+   * session.
+   */
+  void resetInternalState();
 };