diff --git a/packages/react-devtools-extensions/src/inject.js b/packages/react-devtools-extensions/src/inject.js
new file mode 100644
index 0000000000000..938e2cf7eb227
--- /dev/null
+++ b/packages/react-devtools-extensions/src/inject.js
@@ -0,0 +1,24 @@
+/* global chrome */
+
+export default function inject(scriptName: string, done: ?Function) {
+  const source = `
+  // the prototype stuff is in case document.createElement has been modified
+  (function () {
+    var script = document.constructor.prototype.createElement.call(document, 'script');
+    script.src = "${scriptName}";
+    script.charset = "utf-8";
+    document.documentElement.appendChild(script);
+    script.parentNode.removeChild(script);
+  })()
+  `;
+
+  chrome.devtools.inspectedWindow.eval(source, function(response, error) {
+    if (error) {
+      console.log(error);
+    }
+
+    if (typeof done === 'function') {
+      done();
+    }
+  });
+}
diff --git a/packages/react-devtools-extensions/src/injectGlobalHook.js b/packages/react-devtools-extensions/src/injectGlobalHook.js
index 2347671d24a5a..b56f9a299b378 100644
--- a/packages/react-devtools-extensions/src/injectGlobalHook.js
+++ b/packages/react-devtools-extensions/src/injectGlobalHook.js
@@ -24,26 +24,16 @@ let lastDetectionResult;
 // So instead, the hook will use postMessage() to pass message to us here.
 // And when this happens, we'll send a message to the "background page".
 window.addEventListener('message', function(evt) {
-  if (evt.source === window && evt.data) {
-    if (evt.data.source === 'react-devtools-detector') {
-      lastDetectionResult = {
-        hasDetectedReact: true,
-        reactBuildType: evt.data.reactBuildType,
-      };
-      chrome.runtime.sendMessage(lastDetectionResult);
-    } else if (evt.data.source === 'react-devtools-inject-backend') {
-      // The backend is injected by the content script to avoid CSP and Trusted Types violations,
-      // since content scripts can modify the DOM and are not subject to the page's policies.
-      // The prototype stuff is in case document.createElement has been modified.
-      const script = document.constructor.prototype.createElement.call(
-        document,
-        'script',
-      );
-      script.src = chrome.runtime.getURL('build/backend.js');
-      script.charset = 'utf-8';
-      document.documentElement.appendChild(script);
-      script.parentNode.removeChild(script);
-    }
+  if (
+    evt.source === window &&
+    evt.data &&
+    evt.data.source === 'react-devtools-detector'
+  ) {
+    lastDetectionResult = {
+      hasDetectedReact: true,
+      reactBuildType: evt.data.reactBuildType,
+    };
+    chrome.runtime.sendMessage(lastDetectionResult);
   }
 });
 
diff --git a/packages/react-devtools-extensions/src/main.js b/packages/react-devtools-extensions/src/main.js
index d12f002b843a0..7d786e0321917 100644
--- a/packages/react-devtools-extensions/src/main.js
+++ b/packages/react-devtools-extensions/src/main.js
@@ -4,6 +4,7 @@ import {createElement} from 'react';
 import {unstable_createRoot as createRoot, flushSync} from 'react-dom';
 import Bridge from 'react-devtools-shared/src/bridge';
 import Store from 'react-devtools-shared/src/devtools/store';
+import inject from './inject';
 import {
   createViewElementSource,
   getBrowserName,
@@ -134,14 +135,7 @@ function createPanelIfReactLoaded() {
 
         // Initialize the backend only once the Store has been initialized.
         // Otherwise the Store may miss important initial tree op codes.
-        chrome.devtools.inspectedWindow.eval(
-          `window.postMessage({ source: 'react-devtools-inject-backend' });`,
-          function(response, evalError) {
-            if (evalError) {
-              console.log(evalError);
-            }
-          },
-        );
+        inject(chrome.runtime.getURL('build/backend.js'));
 
         const viewElementSourceFunction = createViewElementSource(
           bridge,
@@ -161,6 +155,7 @@ function createPanelIfReactLoaded() {
               overrideTab,
               profilerPortalContainer,
               showTabBar: false,
+              showWelcomeToTheNewDevToolsDialog: true,
               store,
               viewElementSourceFunction,
             }),