diff --git a/package-lock.json b/package-lock.json
index 1d86570cb..ccf3543ab 100644
--- a/package-lock.json
+++ b/package-lock.json
@@ -30,7 +30,7 @@
 				"@wordpress/babel-preset-default": "^7.42.0",
 				"@wordpress/block-editor": "^14.3.0",
 				"@wordpress/blocks": "^13.9.0",
-				"@wordpress/components": "^28.8.0",
+				"@wordpress/components": "^28.9.0",
 				"@wordpress/compose": "^7.9.0",
 				"@wordpress/core-data": "^7.8.0",
 				"@wordpress/data": "^10.9.0",
@@ -9650,11 +9650,10 @@
 			}
 		},
 		"node_modules/@wordpress/components": {
-			"version": "28.8.4",
-			"resolved": "https://registry.npmjs.org/@wordpress/components/-/components-28.8.4.tgz",
-			"integrity": "sha512-w/C2OfLeDoJlPaFFlb9QblLFpPSpGPwztyzjN8cmOHqLh4HVi0Yx+sYotTHYlyv2XWGIBExt8Z2Ea8QoeE2Fcw==",
+			"version": "28.9.0",
+			"resolved": "https://registry.npmjs.org/@wordpress/components/-/components-28.9.0.tgz",
+			"integrity": "sha512-/ept6OSWAh4bdZwlhU8TwJe9QM6rqjAXVA08H0wymtjdRbAQiuDsmMfLFKCF1M4hGZeeThAD5YF0ZkBK5iCeCA==",
 			"dev": true,
-			"license": "GPL-2.0-or-later",
 			"dependencies": {
 				"@ariakit/react": "^0.4.10",
 				"@babel/runtime": "^7.16.0",
@@ -9668,23 +9667,23 @@
 				"@types/gradient-parser": "0.1.3",
 				"@types/highlight-words-core": "1.2.1",
 				"@use-gesture/react": "^10.3.1",
-				"@wordpress/a11y": "^4.8.2",
-				"@wordpress/compose": "^7.8.3",
-				"@wordpress/date": "^5.8.2",
-				"@wordpress/deprecated": "^4.8.2",
-				"@wordpress/dom": "^4.8.2",
-				"@wordpress/element": "^6.8.1",
-				"@wordpress/escape-html": "^3.8.1",
-				"@wordpress/hooks": "^4.8.2",
-				"@wordpress/html-entities": "^4.8.1",
-				"@wordpress/i18n": "^5.8.2",
-				"@wordpress/icons": "^10.8.2",
-				"@wordpress/is-shallow-equal": "^5.8.1",
-				"@wordpress/keycodes": "^4.8.2",
-				"@wordpress/primitives": "^4.8.1",
-				"@wordpress/private-apis": "^1.8.1",
-				"@wordpress/rich-text": "^7.8.3",
-				"@wordpress/warning": "^3.8.1",
+				"@wordpress/a11y": "^4.9.0",
+				"@wordpress/compose": "^7.9.0",
+				"@wordpress/date": "^5.9.0",
+				"@wordpress/deprecated": "^4.9.0",
+				"@wordpress/dom": "^4.9.0",
+				"@wordpress/element": "^6.9.0",
+				"@wordpress/escape-html": "^3.9.0",
+				"@wordpress/hooks": "^4.9.0",
+				"@wordpress/html-entities": "^4.9.0",
+				"@wordpress/i18n": "^5.9.0",
+				"@wordpress/icons": "^10.9.0",
+				"@wordpress/is-shallow-equal": "^5.9.0",
+				"@wordpress/keycodes": "^4.9.0",
+				"@wordpress/primitives": "^4.9.0",
+				"@wordpress/private-apis": "^1.9.0",
+				"@wordpress/rich-text": "^7.9.0",
+				"@wordpress/warning": "^3.9.0",
 				"change-case": "^4.1.2",
 				"clsx": "^2.1.1",
 				"colord": "^2.7.0",
@@ -9712,14 +9711,13 @@
 			}
 		},
 		"node_modules/@wordpress/components/node_modules/@wordpress/keycodes": {
-			"version": "4.8.2",
-			"resolved": "https://registry.npmjs.org/@wordpress/keycodes/-/keycodes-4.8.2.tgz",
-			"integrity": "sha512-BxZD5tk4sDHywV7HOF/hSY924ToW7YJe6hDh4yv+7vo5LpiYQq+/uW21hyXrWEjGXZtdmT1tx69wR16BG35bYw==",
+			"version": "4.9.0",
+			"resolved": "https://registry.npmjs.org/@wordpress/keycodes/-/keycodes-4.9.0.tgz",
+			"integrity": "sha512-WO4MPlO+uGaDP5jYB9f4hn0NgBwvlaUvj4MLOIDcQGE0ljElLGFeXvqjVH0KVtnZkIKiZNPK7eoQxTWnxWaTjw==",
 			"dev": true,
-			"license": "GPL-2.0-or-later",
 			"dependencies": {
 				"@babel/runtime": "^7.16.0",
-				"@wordpress/i18n": "^5.8.2"
+				"@wordpress/i18n": "^5.9.0"
 			},
 			"engines": {
 				"node": ">=18.12.0",
@@ -9727,11 +9725,10 @@
 			}
 		},
 		"node_modules/@wordpress/components/node_modules/@wordpress/warning": {
-			"version": "3.8.1",
-			"resolved": "https://registry.npmjs.org/@wordpress/warning/-/warning-3.8.1.tgz",
-			"integrity": "sha512-xlo0Xw1jiyiE6nh43NAtQMAL05VDk837kY2xfjsus6wD597TeWFpj6gmcRMH25FZULTUHDB2EPfLviWXqOgUfg==",
+			"version": "3.9.0",
+			"resolved": "https://registry.npmjs.org/@wordpress/warning/-/warning-3.9.0.tgz",
+			"integrity": "sha512-c+bEWwDjp3+Q7SAGb47CuZe56giBFNvutoyiAkn34pQZeO8pRjPElRABIkR7oyn4dEusjL1f6OQmU3dSYAMTpg==",
 			"dev": true,
-			"license": "GPL-2.0-or-later",
 			"engines": {
 				"node": ">=18.12.0",
 				"npm": ">=8.19.2"
@@ -9931,14 +9928,13 @@
 			}
 		},
 		"node_modules/@wordpress/date": {
-			"version": "5.8.2",
-			"resolved": "https://registry.npmjs.org/@wordpress/date/-/date-5.8.2.tgz",
-			"integrity": "sha512-ECPE9JXQ0GN+A3ssP+bmEtt122JQnkuXzGOUXfED+kjdmFZ1MgPtyKfXBFDzyW6fPHAwzpSbyFSBXfwxevxWAQ==",
+			"version": "5.9.0",
+			"resolved": "https://registry.npmjs.org/@wordpress/date/-/date-5.9.0.tgz",
+			"integrity": "sha512-Iywz1bga3cPSrf7k4dh2mYVsACqzu0GXYhfu57ElAM9robGjcUxJdzgbWUZw90v473NOp2UpVYsWCuDEqNDcdw==",
 			"dev": true,
-			"license": "GPL-2.0-or-later",
 			"dependencies": {
 				"@babel/runtime": "^7.16.0",
-				"@wordpress/deprecated": "^4.8.2",
+				"@wordpress/deprecated": "^4.9.0",
 				"moment": "^2.29.4",
 				"moment-timezone": "^0.5.40"
 			},
diff --git a/package.json b/package.json
index c52d78e5d..f9000a886 100644
--- a/package.json
+++ b/package.json
@@ -58,7 +58,7 @@
 		"@wordpress/babel-preset-default": "^7.42.0",
 		"@wordpress/block-editor": "^14.3.0",
 		"@wordpress/blocks": "^13.9.0",
-		"@wordpress/components": "^28.8.0",
+		"@wordpress/components": "^28.9.0",
 		"@wordpress/compose": "^7.9.0",
 		"@wordpress/core-data": "^7.8.0",
 		"@wordpress/data": "^10.9.0",
diff --git a/tests/js/content-helper/structure.test.tsx b/tests/js/content-helper/structure.test.tsx
index 637e2582e..9f1ed5e2d 100644
--- a/tests/js/content-helper/structure.test.tsx
+++ b/tests/js/content-helper/structure.test.tsx
@@ -27,6 +27,15 @@ import {
 	RelatedPostsProvider,
 } from '../../../src/content-helper/editor-sidebar/related-posts/provider';
 
+// Avoid "ReferenceError: ResizeObserver is not defined" error.
+window.ResizeObserver =
+	window.ResizeObserver ||
+	jest.fn().mockImplementation( () => ( {
+		disconnect: jest.fn(),
+		observe: jest.fn(),
+		unobserve: jest.fn(),
+	} ) );
+
 // Mock the SettingsProvider component.
 jest.mock( '../../../src/content-helper/common/settings/provider', () => ( {
 	SettingsProvider: ( { children }: { children: React.ReactNode } ) => children,