--- a/devtools/client/responsive.html/browser/tunnel.js
+++ b/devtools/client/responsive.html/browser/tunnel.js
@@ -49,16 +49,19 @@ const SWAPPED_BROWSER_STATE = [
  * needed.
  */
 const PROPERTIES_FROM_BROWSER_WINDOW = [
   // This is used by PermissionUI.jsm for permission doorhangers.
   "PopupNotifications",
   // This is used by ContentClick.jsm when opening links in ways other than just
   // navigating the viewport.
   "whereToOpenLink",
+  // This is used by various event handlers, typically to call `getTabForBrowser` to map
+  // a browser back to a tab.
+  "gBrowser",
 ];
 
 /**
  * This module takes an "outer" <xul:browser> from a browser tab as described by
  * Firefox's tabbrowser.xml and wires it up to an "inner" <iframe mozbrowser>
  * browser element containing arbitrary page content of interest.
  *
  * The inner <iframe mozbrowser> element is _just_ the page content.  It is not