diff --git a/ext/src/main.ts b/ext/src/main.ts
index f9c8172..078a39a 100755
--- a/ext/src/main.ts
+++ b/ext/src/main.ts
@@ -257,6 +257,15 @@ browser.menus.onShown.addListener(info => {
  */
 browser.webRequest.onBeforeRequest.addListener(
         async details => {
+            await browser.tabs.executeScript(details.tabId, {
+                code: `
+                    window.isFramework = ${
+                        details.url === CAST_FRAMEWORK_LOADER_SCRIPT_URL};
+                `
+              , frameId: details.frameId
+              , runAt: "document_start"
+            });
+
             await browser.tabs.executeScript(details.tabId, {
                 file: "shim/contentBridge.js"
               , frameId: details.frameId
diff --git a/ext/src/shim/content.ts b/ext/src/shim/content.ts
index 2de200f..d630174 100644
--- a/ext/src/shim/content.ts
+++ b/ext/src/shim/content.ts
@@ -4,10 +4,7 @@ import { CAST_LOADER_SCRIPT_URL
        , CAST_SCRIPT_URLS } from "../endpoints";
 
 
-const _window = (window.wrappedJSObject as any);
-
-_window.chrome = cloneInto({}, window);
-_window.navigator.presentation = cloneInto({}, window);
+(window.wrappedJSObject as any).chrome = cloneInto({}, window);
 
 
 /**
diff --git a/ext/src/shim/contentBridge.ts b/ext/src/shim/contentBridge.ts
index fc1ea08..50c7bc1 100644
--- a/ext/src/shim/contentBridge.ts
+++ b/ext/src/shim/contentBridge.ts
@@ -1,6 +1,19 @@
 "use strict";
 
 import { onMessageResponse, sendMessage } from "./eventMessageChannel";
+import { loadScript } from "../lib/utils";
+
+
+const { isFramework }
+    : { isFramework: boolean } = (window as any);
+
+/**
+ * Framework API library requires webcomponents for the cast
+ * button custom element (<google-cast-launcher>).
+ */
+if (isFramework) {
+    loadScript(browser.runtime.getURL("vendor/webcomponents-lite.js"));
+}
 
 
 // Message port to background script
diff --git a/ext/src/shim/index.ts b/ext/src/shim/index.ts
index 9ce90d1..c7aab2c 100755
--- a/ext/src/shim/index.ts
+++ b/ext/src/shim/index.ts
@@ -47,12 +47,6 @@ if (document.currentScript) {
 
         isFramework = true;
 
-        /**
-         * Framework API library requires webcomponents for the cast
-         * button custom element (<google-cast-launcher>).
-         */
-        loadScript(browser.runtime.getURL("vendor/webcomponents-lite.js"));
-
         const script = loadScript(CAST_FRAMEWORK_SCRIPT_URL);
         script.addEventListener("load", ev => {
             callPageReadyFunction();