From 512d608a95d50a35ddbfd4250ea7fb2439da8da1 Mon Sep 17 00:00:00 2001
From: Kovid Goyal <kovid@kovidgoyal.net>
Date: Fri, 20 Dec 2013 18:55:10 +0530
Subject: [PATCH] Fix running check book with no book opened gives an error
 message

---
 src/calibre/gui2/tweak_book/boss.py | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/src/calibre/gui2/tweak_book/boss.py b/src/calibre/gui2/tweak_book/boss.py
index e00300b8f5..fb689f6bc9 100644
--- a/src/calibre/gui2/tweak_book/boss.py
+++ b/src/calibre/gui2/tweak_book/boss.py
@@ -795,6 +795,8 @@ class Boss(QObject):
 
     @in_thread_job
     def check_requested(self, *args):
+        if current_container() is None:
+            return
         self.commit_all_editors_to_container()
         c = self.gui.check_book
         c.parent().show()