diff --git a/browser/base/content/sanitizeDialog.js b/browser/base/content/sanitizeDialog.js
index d46780fd6fc6..38d5f1a1a7d5 100644
--- a/browser/base/content/sanitizeDialog.js
+++ b/browser/base/content/sanitizeDialog.js
@@ -34,10 +34,17 @@ var gSanitizePromptDialog = {
     // This is used by selectByTimespan() to determine if the window has loaded.
     this._inited = true;
     this._dialog = document.querySelector("dialog");
-    let { inBrowserWindow = false } = window.arguments?.[0] || {};
-    if (inBrowserWindow) {
+    let arg = window.arguments?.[0] || {};
+    if (arg.inBrowserWindow) {
       this._dialog.setAttribute("inbrowserwindow", "true");
       this._observeTitleForChanges();
+    } else if (arg.wrappedJSObject?.needNativeUI) {
+      document
+        .getElementById("sanitizeDurationChoice")
+        .setAttribute("native", "true");
+      for (let cb of document.querySelectorAll("checkbox")) {
+        cb.setAttribute("native", "true");
+      }
     }
 
     let OKButton = this._dialog.getButton("accept");
diff --git a/browser/modules/Sanitizer.jsm b/browser/modules/Sanitizer.jsm
index 635447c7cbf4..c8cd0e55f139 100644
--- a/browser/modules/Sanitizer.jsm
+++ b/browser/modules/Sanitizer.jsm
@@ -107,13 +107,31 @@ var Sanitizer = {
    * @throws if parentWindow is undefined or doesn't have a gDialogBox.
    */
   showUI(parentWindow) {
-    if (!parentWindow?.gDialogBox) {
-      throw new Error("Sanitizer.showUI expected a browser window argument.");
+    // Treat the hidden window as not being a parent window:
+    if (
+      parentWindow?.document.documentURI ==
+      "chrome://browser/content/hiddenWindowMac.xhtml"
+    ) {
+      parentWindow = null;
+    }
+    if (parentWindow?.gDialogBox) {
+      parentWindow.gDialogBox.open("chrome://browser/content/sanitize.xhtml", {
+        inBrowserWindow: true,
+      });
+    } else {
+      let arg = {
+        needNativeUI: true,
+        QueryInterface: ChromeUtils.generateQI([]),
+      };
+      arg.wrappedJSObject = arg;
+      Services.ww.openWindow(
+        parentWindow,
+        "chrome://browser/content/sanitize.xhtml",
+        "Sanitize",
+        "chrome,titlebar,dialog,centerscreen,modal",
+        arg
+      );
     }
-
-    parentWindow.gDialogBox.open("chrome://browser/content/sanitize.xhtml", {
-      inBrowserWindow: true,
-    });
   },
 
   /**