From f116c9391a5f22e59a85bcd4d0de0edf2d262b8c Mon Sep 17 00:00:00 2001
From: Michael Ratcliffe <mratcliffe@mozilla.com>
Date: Tue, 24 Jun 2014 10:54:50 +0100
Subject: [PATCH] Bug 1028609 - Fix this._elementStyle.rules is undefined in
 rule-view.js r=pbrosset

---
 browser/devtools/styleinspector/rule-view.js | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/browser/devtools/styleinspector/rule-view.js b/browser/devtools/styleinspector/rule-view.js
index ebc87a85e115..160c0f53a8dd 100644
--- a/browser/devtools/styleinspector/rule-view.js
+++ b/browser/devtools/styleinspector/rule-view.js
@@ -1623,6 +1623,10 @@ CssRuleView.prototype = {
     let seenPseudoElement = false;
     let seenNormalElement = false;
 
+    if (!this._elementStyle.rules) {
+      return;
+    }
+
     for (let rule of this._elementStyle.rules) {
       if (rule.domRule.system) {
         continue;