From 0dc5c62b1e8a778680b178ade584e3e6113c8bb6 Mon Sep 17 00:00:00 2001
From: gorhill <rhill@raymondhill.net>
Date: Mon, 16 Feb 2015 11:14:37 -0500
Subject: [PATCH] this fixes #815

---
 src/js/element-picker.js | 14 +++++++++++++-
 1 file changed, 13 insertions(+), 1 deletion(-)

diff --git a/src/js/element-picker.js b/src/js/element-picker.js
index db763964e..07ac090bb 100644
--- a/src/js/element-picker.js
+++ b/src/js/element-picker.js
@@ -158,6 +158,18 @@ try {
 
 /******************************************************************************/
 
+var safeQuerySelectorAll = function(node, selector) {
+    var nodeList;
+    try {
+        nodeList = node.querySelectorAll(selector);
+    } catch (e) {
+        nodeList = [];
+    }
+    return nodeList;
+};
+
+/******************************************************************************/
+
 var pausePicker = function() {
     dialog.parentNode.classList.add('paused');
     svgListening(false);
@@ -354,7 +366,7 @@ var cosmeticFilterFromElement = function(elem, out) {
     // `nth-of-type`. It is preferable to use `nth-of-type` as opposed to
     // `nth-child`, as `nth-of-type` is less volatile.
     var parentNode = elem.parentNode;
-    if ( parentNode !== null && parentNode.querySelectorAll(cssScope + selector).length > 1 ) {
+    if ( parentNode !== null && safeQuerySelectorAll(parentNode, cssScope + selector).length > 1 ) {
         i = 1;
         while ( elem.previousSibling !== null ) {
             elem = elem.previousSibling;