diff --git a/lib/ace/editor.js b/lib/ace/editor.js
index ff3bb3cd..b786d5b7 100644
--- a/lib/ace/editor.js
+++ b/lib/ace/editor.js
@@ -2363,7 +2363,7 @@ config.defineOptions(Editor.prototype, "editor", {
     },
     mergeUndoDeltas: {
         values: [false, true, "always"],
-        initialValue: false
+        initialValue: true
     },
     behavioursEnabled: {initialValue: true},
     wrapBehavioursEnabled: {initialValue: true},