diff --git a/xpfe/global/resources/content/radioBindings.xml b/xpfe/global/resources/content/radioBindings.xml
index 16d58c1b166e..d3f3bf4cb6c7 100644
--- a/xpfe/global/resources/content/radioBindings.xml
+++ b/xpfe/global/resources/content/radioBindings.xml
@@ -20,7 +20,7 @@
     </handlers>
   </binding>
   
-  <binding id="radiogroup">
+  <binding id="radiogroup" extends="xul:box">
 
     <interface>
       <property name="data" onset="this.setAttribute('data',val); return val;"