--- a/devtools/client/responsive.html/browser/tunnel.js
+++ b/devtools/client/responsive.html/browser/tunnel.js
@@ -361,21 +361,29 @@ MessageManagerTunnel.prototype = {
     "SessionStore:update",
     // Messages sent to BrowserTestUtils.jsm
     "browser-test-utils:loadEvent",
   ],
 
   OUTER_TO_INNER_MESSAGE_PREFIXES: [
     // Messages sent from DevTools
     "debug:",
+    // Messages sent from findbar.xml
+    "Findbar:",
+    // Messages sent from RemoteFinder.jsm
+    "Finder:",
   ],
 
   INNER_TO_OUTER_MESSAGE_PREFIXES: [
     // Messages sent to DevTools
     "debug:",
+    // Messages sent to findbar.xml
+    "Findbar:",
+    // Messages sent to RemoteFinder.jsm
+    "Finder:",
   ],
 
   OUTER_TO_INNER_FRAME_SCRIPTS: [
     // DevTools server for OOP frames
     "resource://devtools/server/child.js"
   ],
 
   get outerParentMM() {