Fixed `onMoving` not normalizing the dates again after callback

lib/timeline/component/ItemSet.js

@@ -1384,9 +1384,9 @@ ItemSet.prototype._onDrag = function (event) {
       itemData = this._cloneItemData(itemData);  // convert start and end to the correct type
       me.options.onMoving(itemData, function (itemData) {
         if (itemData) {
-          props.item.setData(itemData);
+          props.item.setData(this._cloneItemData(itemData, 'Date'));
         }
-      });
+      }.bind(this));
     }.bind(this));
 
     this.stackDirty = true; // force re-stacking of all items next redraw
@@ -1908,14 +1908,18 @@ ItemSet.itemSetFromTarget = function(event) {
  * to the type (Date, Moment, ...) configured in the DataSet. If not configured,
  * start and end are converted to Date.
  * @param {Object} itemData, typically `item.data`
+ * @param {string} [type]  Optional Date type. If not provided, the type from the DataSet is taken
  * @return {Object} The cloned object
  * @private
  */
-ItemSet.prototype._cloneItemData = function (itemData) {
+ItemSet.prototype._cloneItemData = function (itemData, type) {
   var clone = util.extend({}, itemData);
 
-  // convert start and end date to the type (Date, Moment, ...) configured in the DataSet
-  var type = this.itemsData.getDataSet()._options.type;
+  if (!type) {
+    // convert start and end date to the type (Date, Moment, ...) configured in the DataSet
+    type = this.itemsData.getDataSet()._options.type;
+  }
+
   if (clone.start != undefined) {
     clone.start = util.convert(clone.start, type && type.start || 'Date');
   }