From 7e89b7a1619a6a672fec7e8913a14315f0b9cd97 Mon Sep 17 00:00:00 2001
From: gorhill <rhill@raymondhill.net>
Date: Sun, 18 Oct 2015 17:18:04 -0400
Subject: [PATCH] attach to window even if a tab browser is not present

---
 platform/firefox/vapi-background.js | 23 ++++++++++++++++++++---
 1 file changed, 20 insertions(+), 3 deletions(-)

diff --git a/platform/firefox/vapi-background.js b/platform/firefox/vapi-background.js
index 6dbb71158..b8d8b6a71 100644
--- a/platform/firefox/vapi-background.js
+++ b/platform/firefox/vapi-background.js
@@ -1112,9 +1112,14 @@ var tabWatcher = (function() {
 
         // On some platforms, the tab browser isn't immediately available,
         // try waiting a bit if this happens.
+        // https://github.com/gorhill/uBlock/issues/763
+        // Not getting a tab browser should not prevent from attaching ourself
+        // to the window.
         var tabBrowser = getTabBrowser(window);
-        if ( tabBrowser === null ) {
-            attachToTabBrowserLater({ window: window, tryCount: tryCount });
+        if (
+            tabBrowser === null &&
+            attachToTabBrowserLater({ window: window, tryCount: tryCount })
+        ) {
             return;
         }
 
@@ -1122,6 +1127,10 @@ var tabWatcher = (function() {
             vAPI.toolbarButton.attachToNewWindow(window);
         }
 
+        if ( tabBrowser === null ) {
+            return;
+        }
+
         var tabContainer;
         if ( tabBrowser.deck ) {                    // Fennec
             tabContainer = tabBrowser.deck;
@@ -1206,7 +1215,15 @@ var tabWatcher = (function() {
 
     // https://developer.mozilla.org/en-US/docs/Mozilla/Tech/XPCOM/Reference/Interface/nsIWindowWatcher
     var windowWatcher = {
-        observe: function(win, topic) {
+        observe: function(subject, topic) {
+            var win;
+            try {
+                win = subject.QueryInterface(Ci.nsIDOMWindow);
+            } catch (ex) {
+            }
+            if ( !win ) {
+                return;
+            }
             if ( topic === 'domwindowopened' ) {
                 onWindowLoad.call(win);
                 return;