diff --git a/lib/ace/edit_session.js b/lib/ace/edit_session.js
index eaf6dca3..5791de72 100644
--- a/lib/ace/edit_session.js
+++ b/lib/ace/edit_session.js
@@ -86,7 +86,7 @@ var EditSession = function(text, mode) {
         return str;
     }
 
-    if (typeof text == "object") {
+    if (typeof text == "object" && text.getLine) {
         this.setDocument(text);
     } else {
         this.setDocument(new Document(text));