diff --git a/lib/ace/edit_session.js b/lib/ace/edit_session.js
index cc34ce6f..69938b6f 100644
--- a/lib/ace/edit_session.js
+++ b/lib/ace/edit_session.js
@@ -1216,7 +1216,7 @@ var EditSession = function(text, mode) {
         var range, point;
         var lastDeltaIsInsert = false;
         if (isInsert(delta)) {
-            range = delta.range.clone();
+            range = Range.fromPoints(delta.range.start, delta.range.end);
             lastDeltaIsInsert = true;
         } else {
             range = Range.fromPoints(delta.range.start, delta.range.start);
@@ -1248,6 +1248,11 @@ var EditSession = function(text, mode) {
         // Check if this range and the last undo range has something in common.
         // If true, merge the ranges.
         if (lastUndoRange != null) {
+            if (Range.comparePoints(lastUndoRange.start, range.start) == 0) {
+                lastUndoRange.start.column += range.end.column - range.start.column;
+                lastUndoRange.end.column += range.end.column - range.start.column;
+            }
+
             var cmp = lastUndoRange.compareRange(range);
             if (cmp == 1) {
                 range.setStart(lastUndoRange.start);