Moved `emit('_change'...)` from Timeline.setItems to ItemSet.setItems to be consistend with ItemSet.setGroups

lib/timeline/Timeline.js

@@ -237,9 +237,6 @@ Timeline.prototype.setItems = function(items) {
   // set items
   this.itemsData = newDataSet;
   this.itemSet && this.itemSet.setItems(newDataSet);
-
-  this.body.emitter.emit('_change', {queue: true});
-
 };
 
 /**

lib/timeline/component/ItemSet.js

@@ -726,6 +726,8 @@ ItemSet.prototype.setItems = function(items) {
     // update the group holding all ungrouped items
     this._updateUngrouped();
   }
+
+  this.body.emitter.emit('_change', {queue: true});
 };
 
 /**