diff --git a/browser/components/customizableui/CustomizableWidgets.jsm b/browser/components/customizableui/CustomizableWidgets.jsm
index 730b14360411..3a70469eba94 100644
--- a/browser/components/customizableui/CustomizableWidgets.jsm
+++ b/browser/components/customizableui/CustomizableWidgets.jsm
@@ -102,6 +102,9 @@ const CustomizableWidgets = [
         case "ViewShowing":
           this.onSubViewShowing(event);
           break;
+        case "unload":
+          this.onWindowUnload(event);
+          break;
         default:
           throw new Error(`Unsupported event for '${this.id}'`);
       }
@@ -166,6 +169,7 @@ const CustomizableWidgets = [
       // When the popup is hidden (thus the panelmultiview node as well), make
       // sure to stop listening to PlacesDatabase updates.
       panelview.panelMultiView.addEventListener("PanelMultiViewHidden", this);
+      window.addEventListener("unload", this);
     },
     onViewHiding(event) {
       log.debug("History view is being hidden!");
@@ -187,6 +191,11 @@ const CustomizableWidgets = [
       }
       panelMultiView.removeEventListener("PanelMultiViewHidden", this);
     },
+    onWindowUnload(event) {
+      if (this._panelMenuView) {
+        delete this._panelMenuView;
+      }
+    },
     onSubViewShowing(event) {
       let panelview = event.target;
       let document = event.target.ownerDocument;
diff --git a/browser/components/customizableui/test/browser_history_recently_closed.js b/browser/components/customizableui/test/browser_history_recently_closed.js
index 89ad09e6cae0..6a286b660aa1 100644
--- a/browser/components/customizableui/test/browser_history_recently_closed.js
+++ b/browser/components/customizableui/test/browser_history_recently_closed.js
@@ -94,3 +94,53 @@ add_task(async function testRecentlyClosedDisabled() {
 
   await hideHistoryPanel();
 });
+
+add_task(async function testRecentlyClosedTabsDisabledPersists() {
+  info("Check history recently closed tabs/windows section");
+
+  CustomizableUI.addWidgetToArea(
+    "history-panelmenu",
+    CustomizableUI.AREA_FIXED_OVERFLOW_PANEL
+  );
+  registerCleanupFunction(() => CustomizableUI.reset());
+
+  // We need to make sure the history is cleared before starting the test
+  await Sanitizer.sanitize(["history"]);
+
+  await openHistoryPanel();
+
+  let recentlyClosedTabs = document.getElementById("appMenuRecentlyClosedTabs");
+  Assert.ok(
+    recentlyClosedTabs.getAttribute("disabled"),
+    "Recently closed tabs button disabled"
+  );
+
+  await hideHistoryPanel();
+
+  let newWin = await BrowserTestUtils.openNewBrowserWindow();
+
+  await openHistoryPanel(newWin.document);
+  recentlyClosedTabs = newWin.document.getElementById(
+    "appMenuRecentlyClosedTabs"
+  );
+  Assert.ok(
+    recentlyClosedTabs.getAttribute("disabled"),
+    "Recently closed tabs is disabled"
+  );
+
+  // We close the window without hiding the panel first, which used to interfere
+  // with populating the view subsequently.
+  await BrowserTestUtils.closeWindow(newWin);
+
+  newWin = await BrowserTestUtils.openNewBrowserWindow();
+  await openHistoryPanel(newWin.document);
+  recentlyClosedTabs = newWin.document.getElementById(
+    "appMenuRecentlyClosedTabs"
+  );
+  Assert.ok(
+    recentlyClosedTabs.getAttribute("disabled"),
+    "Recently closed tabs is disabled"
+  );
+  await hideHistoryPanel(newWin.document);
+  await BrowserTestUtils.closeWindow(newWin);
+});
diff --git a/browser/themes/osx/browser.css b/browser/themes/osx/browser.css
index 80f62302fefd..6f5ffe6790f4 100644
--- a/browser/themes/osx/browser.css
+++ b/browser/themes/osx/browser.css
@@ -86,12 +86,12 @@
 #tabbrowser-tabs {
   --tab-line-color: -moz-accent-color;
 }
-} /* END !proton */
 
 #navigator-toolbox toolbarbutton:-moz-lwtheme {
   color: inherit;
   text-shadow: inherit;
 }
+} /* END !proton */
 
 @media not (-moz-proton) {
 :root[macOSNativeFullscreen]:not(:-moz-lwtheme) :is(#navigator-toolbox, #sidebar-box) {