diff --git a/layout/reftests/bugs/428278-iframe.html b/layout/reftests/bugs/428278-iframe.html
new file mode 100644
index 00000000000..19643e0a4c7
--- /dev/null
+++ b/layout/reftests/bugs/428278-iframe.html
@@ -0,0 +1,10 @@
+<!DOCTYPE HTML>
+<html><head>
+<meta http-equiv="content-type" content="text/html; charset=UTF-8">
+
+
+</head><body>
+<table style="outline-color: red; outline-style: solid; outline-width: medium; border:1px solid black">
+<tr><td style="border:1px solid blue">resize the window
+</table>
+</body></html>
diff --git a/layout/reftests/bugs/428278-ref.html b/layout/reftests/bugs/428278-ref.html
new file mode 100644
index 00000000000..daee98b8839
--- /dev/null
+++ b/layout/reftests/bugs/428278-ref.html
@@ -0,0 +1,9 @@
+<!DOCTYPE HTML>
+<html><head>
+<meta http-equiv="content-type" content="text/html; charset=UTF-8">
+
+
+</head><body>
+
+<iframe id="x" src="428278-iframe.html" style="width:400px"></iframe>
+</body></html>
diff --git a/layout/reftests/bugs/428278.html b/layout/reftests/bugs/428278.html
new file mode 100644
index 00000000000..feed7c77fae
--- /dev/null
+++ b/layout/reftests/bugs/428278.html
@@ -0,0 +1,18 @@
+<!DOCTYPE HTML>
+<html><head>
+<meta http-equiv="content-type" content="text/html; charset=UTF-8">
+
+
+</head><body onload="foo()">
+
+<iframe id="x" src="428278-iframe.html"></iframe>
+<script>
+var w = 400;
+function foo() {
+  var div = document.getElementById('x');
+  div.style.width=w+"px";
+  ++w;
+  var v = document.offsetHeight;
+}
+</script>
+</body></html>
diff --git a/layout/reftests/bugs/reftest.list b/layout/reftests/bugs/reftest.list
index 767e6ab0c86..64fdf157f08 100644
--- a/layout/reftests/bugs/reftest.list
+++ b/layout/reftests/bugs/reftest.list
@@ -841,6 +841,7 @@ fails-if(MOZ_WIDGET_TOOLKIT=="gtk2") == 424074-1-ref2.xul 424074-1-ref3.xul
 == 427129-table-caption.html 427129-table-caption-ref.html
 == 427370-1.html 427370-1-ref.html
 == 427730-1.html 427730-1-ref.html
+== 428278.html 428278-ref.html
 == 428423-1a.html 428423-1-ref.html
 == 428423-1b.html 428423-1-ref.html
 == 428521-1a.html 428521-1-ref.html
