--- a/browser/components/customizableui/CustomizableWidgets.jsm
+++ b/browser/components/customizableui/CustomizableWidgets.jsm
@@ -241,23 +241,16 @@ const CustomizableWidgets = [
         recentlyClosedTabs.removeChild(recentlyClosedTabs.firstChild);
       }
 
       let recentlyClosedWindows = doc.getElementById("PanelUI-recentlyClosedWindows");
       while (recentlyClosedWindows.firstChild) {
         recentlyClosedWindows.removeChild(recentlyClosedWindows.firstChild);
       }
 
-      let tabsFromOtherComputers = doc.getElementById("sync-tabs-menuitem2");
-      if (PlacesUIUtils.shouldShowTabsFromOtherComputersMenuitem()) {
-        tabsFromOtherComputers.removeAttribute("hidden");
-      } else {
-        tabsFromOtherComputers.setAttribute("hidden", true);
-      }
-
       let utils = RecentlyClosedTabsAndWindowsMenuUtils;
       let tabsFragment = utils.getTabsFragment(doc.defaultView, "toolbarbutton", true,
                                                "menuRestoreAllTabsSubview.label");
       let separator = doc.getElementById("PanelUI-recentlyClosedTabs-separator");
       let elementCount = tabsFragment.childElementCount;
       separator.hidden = !elementCount;
       while (--elementCount >= 0) {
         tabsFragment.children[elementCount].classList.add("subviewbutton");

--- a/browser/components/customizableui/content/panelUI.inc.xul
+++ b/browser/components/customizableui/content/panelUI.inc.xul
@@ -79,21 +79,16 @@
                        key="key_gotoHistory"
                        oncommand="SidebarUI.toggle('viewHistorySidebar'); PanelUI.hide();">
           <observes element="viewHistorySidebar" attribute="checked"/>
         </toolbarbutton>
         <toolbarbutton id="appMenuClearRecentHistory"
                        label="&appMenuHistory.clearRecent.label;"
                        class="subviewbutton"
                        command="Tools:Sanitize"/>
-        <toolbarbutton id="sync-tabs-menuitem2"
-                       class="syncTabsMenuItem subviewbutton"
-                       label="&syncTabsMenu3.label;"
-                       oncommand="BrowserOpenSyncTabs();"
-                       hidden="true"/>
         <toolbarbutton id="appMenuRestoreLastSession"
                        label="&appMenuHistory.restoreSession.label;"
                        class="subviewbutton"
                        command="Browser:RestoreLastSession"/>
         <menuseparator id="PanelUI-recentlyClosedTabs-separator"/>
         <vbox id="PanelUI-recentlyClosedTabs" tooltip="bhTooltip"/>
         <menuseparator id="PanelUI-recentlyClosedWindows-separator"/>
         <vbox id="PanelUI-recentlyClosedWindows" tooltip="bhTooltip"/>

--- a/browser/components/customizableui/test/browser.ini
+++ b/browser/components/customizableui/test/browser.ini
@@ -46,19 +46,16 @@ skip-if = os == "linux"
 
 # Bug 1163231 - Causes failures on Developer Edition on Windows 7.
 # [browser_932928_show_notice_when_palette_empty.js]
 
 [browser_934113_menubar_removable.js]
 # Because this test is about the menubar, it can't be run on mac
 skip-if = os == "mac"
 
-[browser_946320_tabs_from_other_computers.js]
-skip-if = os == "linux"
-
 [browser_934951_zoom_in_toolbar.js]
 [browser_938980_navbar_collapsed.js]
 [browser_938995_indefaultstate_nonremovable.js]
 [browser_940013_registerToolbarNode_calls_registerArea.js]
 [browser_940307_panel_click_closure_handling.js]
 [browser_940946_removable_from_navbar_customizemode.js]
 [browser_941083_invalidate_wrapper_cache_createWidget.js]
 [browser_942581_unregisterArea_keeps_placements.js]

deleted file mode 100644
--- a/browser/components/customizableui/test/browser_946320_tabs_from_other_computers.js
+++ /dev/null
@@ -1,144 +0,0 @@
-/* This Source Code Form is subject to the terms of the Mozilla Public
- * License, v. 2.0. If a copy of the MPL was not distributed with this
- * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
-
-"use strict";
-
-var Preferences = Cu.import("resource://gre/modules/Preferences.jsm", {}).Preferences;
-
-const {FxAccounts, AccountState} = Cu.import("resource://gre/modules/FxAccounts.jsm", {});
-
-// FxA logs can be gotten at via this pref which helps debugging.
-Preferences.set("services.sync.log.appender.dump", "Debug");
-
-add_task(function*() {
-  yield PanelUI.show({type: "command"});
-
-  let historyButton = document.getElementById("history-panelmenu");
-  let historySubview = document.getElementById("PanelUI-history");
-  let subviewShownPromise = subviewShown(historySubview);
-  historyButton.click();
-  yield subviewShownPromise;
-
-  let tabsFromOtherComputers = document.getElementById("sync-tabs-menuitem2");
-  is(tabsFromOtherComputers.hidden, true, "The Tabs From Other Computers menuitem should be hidden when sync isn't enabled.");
-
-  let hiddenPanelPromise = promisePanelHidden(window);
-  PanelUI.hide();
-  yield hiddenPanelPromise;
-
-  // Part 2 - When Sync is enabled the menuitem should be shown.
-  yield configureIdentity();
-  yield PanelUI.show({type: "command"});
-
-  subviewShownPromise = subviewShown(historySubview);
-  historyButton.click();
-  yield subviewShownPromise;
-
-  is(tabsFromOtherComputers.hidden, false, "The Tabs From Other Computers menuitem should be shown when sync is enabled.");
-
-  let syncPrefBranch = new Preferences("services.sync.");
-  syncPrefBranch.resetBranch("");
-  Services.logins.removeAllLogins();
-
-  hiddenPanelPromise = promisePanelHidden(window);
-  PanelUI.toggle({type: "command"});
-  yield hiddenPanelPromise;
-
-  yield fxAccounts.signOut(/*localOnly = */true);
-});
-
-function configureIdentity() {
-  // do the FxAccounts thang and wait for Sync to initialize the identity.
-  configureFxAccountIdentity();
-  return Weave.Service.identity.initializeWithCurrentIdentity().then(() => {
-    // need to wait until this identity manager is readyToAuthenticate.
-    return Weave.Service.identity.whenReadyToAuthenticate.promise;
-  });
-}
-
-// Configure an instance of an FxAccount identity provider.
-function configureFxAccountIdentity() {
-  // A mock "storage manager" for FxAccounts that doesn't actually write anywhere.
-  function MockFxaStorageManager() {
-  }
-
-  MockFxaStorageManager.prototype = {
-    promiseInitialized: Promise.resolve(),
-
-    initialize(accountData) {
-      this.accountData = accountData;
-    },
-
-    finalize() {
-      return Promise.resolve();
-    },
-
-    getAccountData() {
-      return Promise.resolve(this.accountData);
-    },
-
-    updateAccountData(updatedFields) {
-      for (let [name, value] of Iterator(updatedFields)) {
-        if (value == null) {
-          delete this.accountData[name];
-        } else {
-          this.accountData[name] = value;
-        }
-      }
-      return Promise.resolve();
-    },
-
-    deleteAccountData() {
-      this.accountData = null;
-      return Promise.resolve();
-    }
-  }
-
-  let user = {
-    assertion: "assertion",
-    email: "email",
-    kA: "kA",
-    kB: "kB",
-    sessionToken: "sessionToken",
-    uid: "user_uid",
-    verified: true,
-  };
-
-  let token = {
-    endpoint: null,
-    duration: 300,
-    id: "id",
-    key: "key",
-    // uid will be set to the username.
-  };
-
-  let MockInternal = {
-    newAccountState(credentials) {
-      isnot(credentials, "not expecting credentials");
-      let storageManager = new MockFxaStorageManager();
-      // and init storage with our user.
-      storageManager.initialize(user);
-      return new AccountState(storageManager);
-    },
-    _getAssertion(audience) {
-      return Promise.resolve("assertion");
-    },
-    getCertificateSigned() {
-      return Promise.resolve();
-    },
-  };
-  let mockTSC = { // TokenServerClient
-    getTokenFromBrowserIDAssertion: function(uri, assertion, cb) {
-      token.uid = "username";
-      cb(null, token);
-    },
-  };
-
-  let fxa = new FxAccounts(MockInternal);
-  Weave.Service.identity._fxaService = fxa;
-  Weave.Service.identity._tokenServerClient = mockTSC;
-  // Set the "account" of the browserId manager to be the "email" of the
-  // logged in user of the mockFXA service.
-  Weave.Service.identity._account = user.email;
-}

--- a/browser/locales/en-US/chrome/browser/browser.dtd
+++ b/browser/locales/en-US/chrome/browser/browser.dtd
@@ -781,17 +781,17 @@ you can use these alternative items. Oth
 
 <!ENTITY identity.permissions "Permissions">
 <!ENTITY identity.permissionsEmpty "You have not granted this site any special permissions.">
 
 <!-- Name for the tabs toolbar as spoken by screen readers.
      The word "toolbar" is appended automatically and should not be contained below! -->
 <!ENTITY tabsToolbar.label "Browser tabs">
 
-<!-- LOCALIZATION NOTE (syncTabsMenu3.label): This appears in the history menu and history panel -->
+<!-- LOCALIZATION NOTE (syncTabsMenu3.label): This appears in the history menu -->
 <!ENTITY syncTabsMenu3.label     "Synced Tabs">
 
 <!ENTITY syncedTabs.sidebar.label              "Synced Tabs">
 <!ENTITY syncedTabs.sidebar.fetching.label     "Fetching Synced Tabs…">
 <!ENTITY syncedTabs.sidebar.noclients.label    "Sign in to Firefox from your other devices to view their tabs here.">
 <!ENTITY syncedTabs.sidebar.notsignedin.label  "Sign in to view a list of tabs from your other devices.">
 <!ENTITY syncedTabs.sidebar.notabs.label       "No open tabs">
 <!ENTITY syncedTabs.sidebar.openprefs.label    "Open &syncBrand.shortName.label; Preferences">