diff --git a/addons/web/static/lib/bootstrap/js/dist/dropdown.js b/addons/web/static/lib/bootstrap/js/dist/dropdown.js
index d0b872d5dc5..f8799b92ae1 100644
--- a/addons/web/static/lib/bootstrap/js/dist/dropdown.js
+++ b/addons/web/static/lib/bootstrap/js/dist/dropdown.js
@@ -257,6 +257,7 @@
   const CLASS_NAME_NAVBAR = 'navbar';
   const SELECTOR_DATA_TOGGLE = '[data-bs-toggle="dropdown"]';
   const SELECTOR_MENU = '.dropdown-menu:not(.o-dropdown--menu)';
+  const SELECTOR_MENU_NOT_SUB = '.dropdown-menu:not(.o-dropdown--menu):not(.o_wysiwyg_submenu)';
   const SELECTOR_NAVBAR_NAV = '.navbar-nav';
   const SELECTOR_VISIBLE_ITEMS = '.dropdown-menu .dropdown-item:not(.disabled):not(:disabled)';
   const PLACEMENT_TOP = isRTL() ? 'top-end' : 'top-start';
@@ -665,7 +666,7 @@
 
 
   EventHandler__default.default.on(document, EVENT_KEYDOWN_DATA_API, SELECTOR_DATA_TOGGLE, Dropdown.dataApiKeydownHandler);
-  EventHandler__default.default.on(document, EVENT_KEYDOWN_DATA_API, SELECTOR_MENU, Dropdown.dataApiKeydownHandler);
+  EventHandler__default.default.on(document, EVENT_KEYDOWN_DATA_API, SELECTOR_MENU_NOT_SUB, Dropdown.dataApiKeydownHandler);
   EventHandler__default.default.on(document, EVENT_CLICK_DATA_API, Dropdown.clearMenus);
   EventHandler__default.default.on(document, EVENT_KEYUP_DATA_API, Dropdown.clearMenus);
   EventHandler__default.default.on(document, EVENT_CLICK_DATA_API, SELECTOR_DATA_TOGGLE, function (event) {
diff --git a/addons/website/static/src/components/wysiwyg_adapter/wysiwyg_adapter.js b/addons/website/static/src/components/wysiwyg_adapter/wysiwyg_adapter.js
index 9e2597fe8b2..dc27b31ef6a 100644
--- a/addons/website/static/src/components/wysiwyg_adapter/wysiwyg_adapter.js
+++ b/addons/website/static/src/components/wysiwyg_adapter/wysiwyg_adapter.js
@@ -168,6 +168,8 @@ export class WysiwygAdapterComponent extends Wysiwyg {
         // Dropdown menu initialization: handle dropdown openings by hand
         var $dropdownMenuToggles = $editableWindow.$('.o_mega_menu_toggle, #o_main_nav .dropdown-toggle');
         $dropdownMenuToggles.removeAttr('data-bs-toggle').dropdown('dispose');
+        // Since bootstrap 5.1.3, removing bsToggle is not sufficient anymore.
+        $dropdownMenuToggles.siblings(".dropdown-menu").addClass("o_wysiwyg_submenu");
         $dropdownMenuToggles.on('click.wysiwyg_megamenu', ev => {
             this.odooEditor.observerUnactive();
             var $toggle = $(ev.currentTarget);
@@ -935,7 +937,7 @@ export class WysiwygAdapterComponent extends Wysiwyg {
             // FIXME normally removing the 'show' class should not be necessary here
             // TODO check that editor classes are removed here as well
             const classes = [...$el[0].classList].filter(megaMenuClass =>
-                ["dropdown-menu", "o_mega_menu", "show"].indexOf(megaMenuClass) < 0);
+                ["dropdown-menu", "o_mega_menu", "show", "o_wysiwyg_submenu"].indexOf(megaMenuClass) < 0);
             promises.push(
                 this.orm.write('website.menu', [parseInt($el.data('oe-id'))], {
                     'mega_menu_classes': classes.join(' '),
diff --git a/addons/website/static/tests/tours/edit_megamenu.js b/addons/website/static/tests/tours/edit_megamenu.js
index 30b18d7b533..91f0716637c 100644
--- a/addons/website/static/tests/tours/edit_megamenu.js
+++ b/addons/website/static/tests/tours/edit_megamenu.js
@@ -85,6 +85,14 @@ wTourUtils.registerWebsitePreviewTour('edit_megamenu', {
         allowInvisible: true,
         run: 'text New Menu Item',
     },
+    {
+        // If this step fails, it means that a patch inside bootstrap was lost.
+        content: "Press the 'down arrow' key.",
+        trigger: 'iframe .o_mega_menu h4',
+        run: function (actions) {
+            this.$anchor[0].dispatchEvent(new window.KeyboardEvent("keydown", { key: "ArrowDown" }));
+        },
+    },
     ...wTourUtils.clickOnSave(),
     wTourUtils.clickOnExtraMenuItem({}, true),
     toggleMegaMenu(),
diff --git a/addons/website/static/tests/tours/edit_menus.js b/addons/website/static/tests/tours/edit_menus.js
index 9d5feb49ce6..101c8e39d69 100644
--- a/addons/website/static/tests/tours/edit_menus.js
+++ b/addons/website/static/tests/tours/edit_menus.js
@@ -274,5 +274,18 @@ wTourUtils.registerWebsitePreviewTour('edit_menus', {
         trigger: 'iframe #top_menu .nav-item:has(a.o_mega_menu_toggle:contains("Megaaaaa!")) ' +
                  '.s_mega_menu_odoo_menu',
         run: () => {}, // It's a check.
-    }
+    },
+    ...wTourUtils.clickOnEditAndWaitEditMode(),
+    {
+        content: "Open nested menu item",
+        trigger: 'iframe #top_menu .nav-item:contains("Home"):nth(1) .dropdown-toggle',
+    },
+    {
+        // If this step fails, it means that a patch inside bootstrap was lost.
+        content: "Press the 'down arrow' key.",
+        trigger: 'iframe #top_menu .nav-item:contains("Home") li:contains("Contact us")',
+        run: function (actions) {
+            this.$anchor[0].dispatchEvent(new window.KeyboardEvent("keydown", { key: "ArrowDown" }));
+        },
+    },
 ]);