diff --git a/layout/reftests/bugs/346189-1-ref.xul b/layout/reftests/bugs/346189-1-ref.xul
index e4839b3790c..d13dca51625 100644
--- a/layout/reftests/bugs/346189-1-ref.xul
+++ b/layout/reftests/bugs/346189-1-ref.xul
@@ -4,7 +4,6 @@
 
 <window
   xmlns="http://www.mozilla.org/keymaster/gatekeeper/there.is.only.xul"
-  xmlns:html="http://www.w3c.org/1999/xhtml"
   width="400"
   height="600">
 
diff --git a/layout/reftests/bugs/346189-1.xul b/layout/reftests/bugs/346189-1.xul
index 59ff2334384..62acfb8e9e7 100644
--- a/layout/reftests/bugs/346189-1.xul
+++ b/layout/reftests/bugs/346189-1.xul
@@ -4,7 +4,6 @@
 
 <window
   xmlns="http://www.mozilla.org/keymaster/gatekeeper/there.is.only.xul"
-  xmlns:html="http://www.w3c.org/1999/xhtml"
   width="400"
   height="600">