diff --git a/layout/reftests/bugs/495274-1-ref.html b/layout/reftests/bugs/495274-1-ref.html
new file mode 100644
index 000000000000..882f0ef9fc2e
--- /dev/null
+++ b/layout/reftests/bugs/495274-1-ref.html
@@ -0,0 +1,9 @@
+<!DOCTYPE html>
+<html>
+  <head>
+    <style>body { color: green; }</style>
+  </head>
+  <body>
+    This text should be green
+  </body>
+</html>
diff --git a/layout/reftests/bugs/495274-1.html b/layout/reftests/bugs/495274-1.html
new file mode 100644
index 000000000000..2a0b3a85a64e
--- /dev/null
+++ b/layout/reftests/bugs/495274-1.html
@@ -0,0 +1,15 @@
+<!DOCTYPE html>
+<html>
+  <head>
+    <style>body { color: green; }</style>
+    <link rel="stylesheet" href='data:text/css,body > span { color: red }' type="text/css"/>
+    <link rel="stylesheet" href='data:text/css,body > span { color: red }' type="text/css"/>
+    <script>
+      // Force cloning of the second linked sheet
+      document.styleSheets[2].cssRules[0];
+    </script>
+  </head>
+  <body>
+    <div><span>This text should be green</span></div>
+  </body>
+</html>
diff --git a/layout/reftests/bugs/reftest.list b/layout/reftests/bugs/reftest.list
index 0eb0ed690978..d95d719f7afb 100644
--- a/layout/reftests/bugs/reftest.list
+++ b/layout/reftests/bugs/reftest.list
@@ -1242,3 +1242,4 @@ fails-if(MOZ_WIDGET_TOOLKIT!="cocoa") == 488692-1.html 488692-1-ref.html # needs
 == 493968-1.html 493968-1-ref.html
 == 494667-1.html 494667-1-ref.html
 == 494667-2.html 494667-2-ref.html
+== 495274-1.html 495274-1-ref.html
diff --git a/layout/style/nsCSSStyleRule.cpp b/layout/style/nsCSSStyleRule.cpp
index e4143d1250c9..b49074141098 100644
--- a/layout/style/nsCSSStyleRule.cpp
+++ b/layout/style/nsCSSStyleRule.cpp
@@ -280,6 +280,7 @@ nsCSSSelector::Clone(PRBool aDeepNext, PRBool aDeepNegations) const
 
   result->mNameSpace = mNameSpace;
   result->mTag = mTag;
+  result->mOperator = mOperator;
   
   NS_IF_CLONE(mIDList);
   NS_IF_CLONE(mClassList);
