From 8967c57252905c62b2f51f3a843d778585d8a18b Mon Sep 17 00:00:00 2001
From: Kovid Goyal <kovid@kovidgoyal.net>
Date: Fri, 25 Apr 2014 14:50:33 +0530
Subject: [PATCH] ...

---
 src/calibre/gui2/ui.py | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/src/calibre/gui2/ui.py b/src/calibre/gui2/ui.py
index 4cfbcc019a..b762bf7b11 100644
--- a/src/calibre/gui2/ui.py
+++ b/src/calibre/gui2/ui.py
@@ -71,7 +71,8 @@ class Listener(Thread):  # {{{
     def close(self):
         self._run = False
         try:
-            self.listener.close()
+            if self.listener is not None:
+                self.listener.close()
         except:
             import traceback
             traceback.print_exc()