diff --git a/lib/ace/edit_session.js b/lib/ace/edit_session.js
index 8b187fe5..6c33c449 100644
--- a/lib/ace/edit_session.js
+++ b/lib/ace/edit_session.js
@@ -86,7 +86,7 @@ var EditSession = function(text, mode) {
     this.onChange = function(e) {
         var delta = e.data;
         this.$modified = true;
-        if (!this.$fromUndo && this.$undoManager) {
+        if (!this.$fromUndo && this.$undoManager && !delta.ignore) {
             this.$deltas.push(delta);
             this.$informUndoManager.schedule();
         }