diff --git a/modules/ve2/dm/ve.dm.Transaction.js b/modules/ve2/dm/ve.dm.Transaction.js
index 2f91cc5b8e..6eab341a5c 100644
--- a/modules/ve2/dm/ve.dm.Transaction.js
+++ b/modules/ve2/dm/ve.dm.Transaction.js
@@ -56,6 +56,7 @@ ve.dm.Transaction.prototype.pushRetain = function( length ) {
  * @param {Array} data Data to retain
  */
 ve.dm.Transaction.prototype.pushInsert = function( data ) {
+	// FIXME use replace operations instead
 	var end = this.operations.length - 1;
 	if ( this.operations.length && this.operations[end].type === 'insert' ) {
 		this.operations[end].data = this.operations[end].data.concat( data );
@@ -75,6 +76,7 @@ ve.dm.Transaction.prototype.pushInsert = function( data ) {
  * @param {Array} data Data to remove
  */
 ve.dm.Transaction.prototype.pushRemove = function( data ) {
+	// FIXME use replace operations instead
 	var end = this.operations.length - 1;
 	if ( this.operations.length && this.operations[end].type === 'remove' ) {
 		this.operations[end].data = this.operations[end].data.concat( data );