--- a/implementation.js	Wed Aug 03 12:26:01 2011 -0600
+++ b/implementation.js	Wed Aug 03 12:28:29 2011 -0600
@@ -744,7 +744,7 @@
 		&& (node.contentEditable == "true"
 		|| (node.parentNode
 		&& node.parentNode.nodeType == Node.DOCUMENT_NODE
-		&& node.parentNodedesignMode == "on"));
+		&& node.parentNode.designMode == "on"));
 }
 
 // "Something is editable if it is a node which is not an editing host, does