diff --git a/lib/ace/edit_session/folding.js b/lib/ace/edit_session/folding.js
index 9c3562db..36565555 100644
--- a/lib/ace/edit_session/folding.js
+++ b/lib/ace/edit_session/folding.js
@@ -625,7 +625,7 @@ function Folding() {
 
     this.foldAll = function(startRow, endRow) {
         var foldWidgets = this.foldWidgets;
-        endRow = endRow || foldWidgets.length;
+        endRow = endRow || this.getLength();
         for (var row = startRow || 0; row < endRow; row++) {
             if (foldWidgets[row] == null)
                 foldWidgets[row] = this.getFoldWidget(row);