From 13ef7eeb63487badc144b15191e4c177c78f9e82 Mon Sep 17 00:00:00 2001
From: Joshua Walsh <josh@ymindustries.com>
Date: Wed, 21 Jun 2017 03:25:14 +1000
Subject: [PATCH] Fixed #3183 (#3184)

Fixes a race condition that set an item's group to be set to undefined
if it was dropped and then dragged again without a redraw happening in
between.
---
 lib/timeline/component/ItemSet.js | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/lib/timeline/component/ItemSet.js b/lib/timeline/component/ItemSet.js
index 0aa845b9..e5e168a3 100644
--- a/lib/timeline/component/ItemSet.js
+++ b/lib/timeline/component/ItemSet.js
@@ -1342,6 +1342,12 @@ ItemSet.prototype._onDragStart = function (event) {
       this.touchParams.itemProps = [props];
     }
     else {
+      if(this.groupIds.length < 1) {
+        // Mitigates a race condition if _onDragStart() is
+        // called after markDirty() without redraw() being called between.
+        this.redraw();
+      }
+      
       var baseGroupIndex = this._getGroupIndex(item.data.group);
 
       var itemsToDrag = (this.options.itemsAlwaysDraggable.item && !item.selected) ? [item.id] : this.getSelection();