diff --git a/layout/reftests/bugs/894931-1-ref.html b/layout/reftests/bugs/894931-1-ref.html
new file mode 100644
index 000000000000..bed8ffb61f95
--- /dev/null
+++ b/layout/reftests/bugs/894931-1-ref.html
@@ -0,0 +1,8 @@
+<!DOCTYPE HTML>
+<html>
+<body>
+<div style="position:relative; margin-top:100px;">
+  <div style="background:yellow; width:100px; height:100px; position:absolute"></div>
+</div>
+</body>
+</html>
diff --git a/layout/reftests/bugs/894931-1.html b/layout/reftests/bugs/894931-1.html
new file mode 100644
index 000000000000..2ff2ebc90fba
--- /dev/null
+++ b/layout/reftests/bugs/894931-1.html
@@ -0,0 +1,15 @@
+<!DOCTYPE HTML>
+<html class="reftest-wait">
+<body>
+<div id="d" style="margin-top:100px;">
+  <div style="background:yellow; width:100px; height:100px; position:absolute; top:0; left:0"></div>
+</div>
+<script>
+function doTest() {
+  document.getElementById("d").style.position = "relative";
+  document.documentElement.removeAttribute("class");
+}
+window.addEventListener("MozReftestInvalidate", doTest, false);
+</script>
+</body>
+</html>
diff --git a/layout/reftests/bugs/reftest.list b/layout/reftests/bugs/reftest.list
index 7791fd7683f8..3945b9790a50 100644
--- a/layout/reftests/bugs/reftest.list
+++ b/layout/reftests/bugs/reftest.list
@@ -1770,3 +1770,4 @@ random-if(Android&&AndroidVersion>=15) == 875060-1.html 875060-1-ref.html #Bug 8
 == 883987-1e.html 883987-1-ref.html
 == 883987-1f.html 883987-1-ref.html
 == 890495-1.html 890495-1-ref.html
+== 894931-1.html 894931-1-ref.html
