From 594cc7cbef4f8ee57b316b98e86e1a82a5074904 Mon Sep 17 00:00:00 2001
From: Xiaoguang Wang <xwang@suse.com>
Date: Wed, 20 Sep 2017 09:05:16 +0800
Subject: [PATCH] workspaceThumbnails: Avoid access to undefined variables

If thumbnails haven't been created, they don't need to be destroyed.

https://bugzilla.gnome.org/show_bug.cgi?id=787871
---
 js/ui/workspaceThumbnail.js | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/js/ui/workspaceThumbnail.js b/js/ui/workspaceThumbnail.js
index c1b4bddc6..1ecdd92cc 100644
--- a/js/ui/workspaceThumbnail.js
+++ b/js/ui/workspaceThumbnail.js
@@ -884,6 +884,9 @@ var ThumbnailsBox = new Lang.Class({
     },
 
     _destroyThumbnails() {
+        if (this._thumbnails.length == 0)
+            return;
+
         if (this._switchWorkspaceNotifyId > 0) {
             global.window_manager.disconnect(this._switchWorkspaceNotifyId);
             this._switchWorkspaceNotifyId = 0;