diff --git a/lib/ace/editor.js b/lib/ace/editor.js
index 92a10add..ce36ae47 100644
--- a/lib/ace/editor.js
+++ b/lib/ace/editor.js
@@ -1457,7 +1457,7 @@ var Editor = function(renderer, session) {
         } else {
             var ranges = selection.rangeList.ranges;
             selection.rangeList.detach(this.session);
-            
+
             for (var i = ranges.length; i--; ) {
                 var rangeIndex = i;
                 var rows = ranges[i].collapseRows();
@@ -1471,7 +1471,7 @@ var Editor = function(renderer, session) {
                         break;
                 }
                 i++;
-                
+
                 var linesMoved = mover.call(this, first, last);
                 while (rangeIndex >= i) {
                     ranges[rangeIndex].moveBy(linesMoved, 0);
@@ -2210,7 +2210,8 @@ config.defineOptions(Editor.prototype, "editor", {
     readOnly: {
         set: function(readOnly) {
             this.textInput.setReadOnly(readOnly);
-            this.renderer.$cursorLayer.setBlinking(!readOnly);
+            var cursorLayer = this.renderer.$cursorLayer;
+            cursorLayer && cursorLayer.setBlinking(!readOnly);
         },
         initialValue: false
     },