From cc020b901a2f567b7177a8b82ae04aa689f97cf0 Mon Sep 17 00:00:00 2001
From: Hzj_jie <Hzj_jie@hotmail.com>
Date: Sat, 20 May 2017 23:36:41 -0700
Subject: [PATCH] Fix KOsync crash when closing document (#2911)

---
 plugins/kosync.koplugin/main.lua | 1 +
 1 file changed, 1 insertion(+)

diff --git a/plugins/kosync.koplugin/main.lua b/plugins/kosync.koplugin/main.lua
index 29aa888ab..1234b7fb9 100644
--- a/plugins/kosync.koplugin/main.lua
+++ b/plugins/kosync.koplugin/main.lua
@@ -605,6 +605,7 @@ function KOSync:_onResume()
 end
 
 function KOSync:_onFlushSettings()
+    if self.ui == nil or self.ui.document == nil then return end
     self:updateProgress()
 end