diff --git a/layout/reftests/bugs/503531-1-ref.html b/layout/reftests/bugs/503531-1-ref.html
new file mode 100644
index 000000000000..e04c3886dad7
--- /dev/null
+++ b/layout/reftests/bugs/503531-1-ref.html
@@ -0,0 +1,23 @@
+<html class="reftest-wait"><head>
+    <meta http-equiv="Content-Type" content="text/html; charset=iso-8859-1">
+    <title>Testcase #1 for bug 503531</title>
+<script>
+function boom() {
+  var caret = document.getElementById('caret');
+
+  var sel = window.getSelection();
+  sel.removeAllRanges();
+  var range = document.createRange();
+  range.selectNode(caret);
+  sel.addRange(range);
+  sel.collapseToStart();
+
+  setTimeout(function(){document.documentElement.className = '';}, 50)
+}
+</script>
+</head>
+<body contenteditable="true" onload="document.body.focus(); boom()">
+<div>BLOCK</div>
+<div id="caret"></div>
+</body>
+</html>
diff --git a/layout/reftests/bugs/503531-1.html b/layout/reftests/bugs/503531-1.html
new file mode 100644
index 000000000000..3587d85b07bd
--- /dev/null
+++ b/layout/reftests/bugs/503531-1.html
@@ -0,0 +1,25 @@
+<html class="reftest-wait"><head>
+    <meta http-equiv="Content-Type" content="text/html; charset=iso-8859-1">
+    <title>Testcase #1 for bug 503531</title>
+<script>
+function boom() {
+  var emptyText = document.createTextNode('x');
+  document.body.appendChild(emptyText);
+
+  var sel = window.getSelection();
+  sel.removeAllRanges();
+  var range = document.createRange();
+  range.selectNode(emptyText);
+  sel.addRange(range);
+  sel.collapseToStart();
+
+  emptyText.nodeValue='';
+  
+  setTimeout(function(){document.documentElement.className = '';}, 50)
+}
+</script>
+</head>
+<body contenteditable="true" onload="document.body.focus(); boom()">
+<div>BLOCK</div>
+</body>
+</html>
diff --git a/layout/reftests/bugs/reftest.list b/layout/reftests/bugs/reftest.list
index 15589da8393b..9a5065da7133 100644
--- a/layout/reftests/bugs/reftest.list
+++ b/layout/reftests/bugs/reftest.list
@@ -1324,6 +1324,7 @@ fails-if(MOZ_WIDGET_TOOLKIT!="cocoa") == 488692-1.html 488692-1-ref.html # needs
 == 503364-1a.html 503364-1-ref.html
 == 503364-1b.html 503364-1-ref.html
 == 503399.html 503399-ref.html
+== 503531-1.html 503531-1-ref.html
 == 504032-1.html 504032-1-ref.html
 == 505743-1.html about:blank
 == 506481-1.html 506481-1-ref.html
