--- mcomix-0.95/mcomix/main.py.debug	2011-11-05 05:13:53.000000000 +0900
+++ mcomix-0.95/mcomix/main.py	2011-12-14 13:17:17.554104349 +0900
@@ -1120,7 +1120,8 @@
             if thread is not threading.currentThread():
                 thread.join()
 
-        gtk.main_quit()
+        if gtk.main_level() > 0:
+            gtk.main_quit()
 
 #: Main window instance
 __main_window = None