--- a/templates/index.html
+++ b/templates/index.html
@@ -185,7 +185,7 @@
     }
     function editTreeJSON() {
       var json = $('#tree-json-loaded').val();
-      window.open('/editor?json='+json);
+      window.open("{{ url_for('editor') }}?json="+json);
     }
 	</script>
 	<script type="text/javascript" src="static/jit.js"></script>