fixes #2367 Group editable bug (#2368)

* Fix groupEditable
* Fix group drag in vertical direction bug
* Fix indentation

lib/timeline/component/ItemSet.js

@@ -243,7 +243,7 @@ ItemSet.prototype._create = function(){
   this.groupHammer.on('panstart', this._onGroupDragStart.bind(this));
   this.groupHammer.on('panmove',  this._onGroupDrag.bind(this));
   this.groupHammer.on('panend',   this._onGroupDragEnd.bind(this));
-  this.groupHammer.get('pan').set({threshold:5, direction: Hammer.DIRECTION_HORIZONTAL});
+  this.groupHammer.get('pan').set({threshold:5, direction: Hammer.DIRECTION_VERTICAL});
   
   this.body.dom.centerContainer.addEventListener('mouseover', this._onMouseOver.bind(this));
   this.body.dom.centerContainer.addEventListener('mouseout', this._onMouseOut.bind(this));
@@ -1578,6 +1578,10 @@ ItemSet.prototype._onGroupDrag = function (event) {
 	if (this.options.groupEditable.order && this.groupTouchParams.group) {
 		event.stopPropagation();
 		
+    var groupsData = this.groupsData;
+    if (this.groupsData instanceof DataView) {
+      groupsData = this.groupsData.getDataSet()
+    }
 		// drag from one group to another
 		var group = this.groupFromTarget(event);
 		
@@ -1602,25 +1606,23 @@ ItemSet.prototype._onGroupDrag = function (event) {
 		}
 		
 		if (group && group != this.groupTouchParams.group) {
-			var groupsData = this.groupsData;
 			var targetGroup = groupsData.get(group.groupId);
 			var draggedGroup = groupsData.get(this.groupTouchParams.group.groupId);
 			
 			// switch groups
 			if (draggedGroup && targetGroup) {
 				this.options.groupOrderSwap(draggedGroup, targetGroup, this.groupsData);
-				this.groupsData.update(draggedGroup);
-				this.groupsData.update(targetGroup);
+  				groupsData.update(draggedGroup);
+        			groupsData.update(targetGroup);
 			}
 			
 			// fetch current order of groups
-			var newOrder = this.groupsData.getIds({
+			var newOrder = groupsData.getIds({
 			    order: this.options.groupOrder
-		    });
+		    	});
 			
 			// in case of changes since _onGroupDragStart
 			if (!util.equalArray(newOrder, this.groupTouchParams.originalOrder)) {
-				var groupsData = this.groupsData;
 				var origOrder = this.groupTouchParams.originalOrder;
 				var draggedId = this.groupTouchParams.group.groupId;
 				var numGroups = Math.min(origOrder.length, newOrder.length);