diff --git a/browser/base/content/navigator-toolbox.js b/browser/base/content/navigator-toolbox.js
index 362a85c20d8f0633fa78f85578e4cf015fdd0e44..ef7d6ff9e0e9876bc1918e365fd0addcd177cecb 100644
--- a/browser/base/content/navigator-toolbox.js
+++ b/browser/base/content/navigator-toolbox.js
@@ -11,7 +11,7 @@ ChromeUtils.defineESModuleGetters(this, {
 document.addEventListener(
   "DOMContentLoaded",
   () => {
-    const navigatorToolbox = document.getElementById("navigator-toolbox");
+    const navigatorToolbox = document.getElementById("browser");
     const widgetOverflow = document.getElementById("widget-overflow");
 
     function onPopupShowing(event) {
@@ -189,6 +189,7 @@ document.addEventListener(
         #forward-button,
         #reload-button ,
         #reader-mode-button,
+        #zen-tabs-wrapper,
         #picture-in-picture-button,
         #urlbar-zoom-button,
         #star-button-box,
@@ -215,6 +216,17 @@ document.addEventListener(
           gBrowser.handleNewTabMiddleClick(element, event);
           break;
 
+        case "zen-tabs-wrapper":
+          if (event.button == 1) {
+            BrowserCommands.openTab();
+            // Stop the propagation of the click event, to prevent the event from being
+            // handled more than once.
+            // E.g. see https://bugzilla.mozilla.org/show_bug.cgi?id=1657992#c4
+            event.stopPropagation();
+            event.preventDefault();
+          }
+          break;
+
         case "back-button":
         case "forward-button":
         case "reload-button":
@@ -330,6 +342,7 @@ document.addEventListener(
         #downloads-button,
         #fxa-toolbar-menu-button,
         #unified-extensions-button,
+        #zen-site-data-icon-button,
         #library-button,
         #split-view-button,
         #smartwindow-ask-button
@@ -414,6 +427,16 @@ document.addEventListener(
           gUnifiedExtensions.togglePanel(event);
           break;
 
+        case "zen-site-data-icon-button":
+          gUnifiedExtensions.togglePanel(
+            event,
+            null,
+            window.gZenSiteDataPanel.unifiedPanel,
+            window.gZenSiteDataPanel.unifiedPanelView,
+            window.gZenSiteDataPanel.anchor,
+          );
+          break;
+
         case "library-button":
           PanelUI.showSubView("appMenu-libraryView", element, event);
           break;
