From a9089b3120d8f9fa7074a7c9132a12af801c0243 Mon Sep 17 00:00:00 2001
From: gorhill <rhill@raymondhill.net>
Date: Tue, 7 Jul 2015 12:11:11 -0400
Subject: [PATCH] this fixes #452

---
 platform/firefox/frameModule.js | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/platform/firefox/frameModule.js b/platform/firefox/frameModule.js
index 79c3c3353..7a0d84ded 100644
--- a/platform/firefox/frameModule.js
+++ b/platform/firefox/frameModule.js
@@ -163,7 +163,11 @@ const contentObserver = {
                 context.opener !== context &&
                 this.ignoredPopups.has(context) === false
             ) {
-                openerURL = context.opener.location.href;
+                // https://github.com/gorhill/uBlock/issues/452
+                // Use location of top window, not that of a frame, as this
+                // would cause tab id lookup (necessary for popup blocking) to
+                // always fail.
+                openerURL = context.opener.top && context.opener.top.location.href;
             }
         } else if ( type === this.SUB_FRAME ) {
             context = context.contentWindow;