From 716d55e869273304bff4ca73a0364e23d4523516 Mon Sep 17 00:00:00 2001
From: Kovid Goyal <kovid@kovidgoyal.net>
Date: Wed, 30 Jan 2013 14:49:48 +0530
Subject: [PATCH] ...

---
 src/calibre/gui2/metadata/pdf_covers.py | 3 ++-
 src/calibre/gui2/metadata/single.py     | 2 +-
 2 files changed, 3 insertions(+), 2 deletions(-)

diff --git a/src/calibre/gui2/metadata/pdf_covers.py b/src/calibre/gui2/metadata/pdf_covers.py
index 7e493a2188..b53d12d70b 100644
--- a/src/calibre/gui2/metadata/pdf_covers.py
+++ b/src/calibre/gui2/metadata/pdf_covers.py
@@ -11,6 +11,7 @@ import sys, shutil, os
 from threading import Thread
 from glob import glob
 
+import sip
 from PyQt4.Qt import (QDialog, QApplication, QLabel, QGridLayout,
                       QDialogButtonBox, Qt, pyqtSignal, QListWidget,
                       QListWidgetItem, QSize, QIcon)
@@ -76,7 +77,7 @@ class PDFCovers(QDialog):
             page_images(self.pdfpath, self.tdir, last=10)
         except Exception as e:
             self.error = as_unicode(e)
-        if self.isVisible():
+        if not sip.isdeleted(self) and self.isVisible():
             self.rendering_done.emit()
 
     def show_pages(self):
diff --git a/src/calibre/gui2/metadata/single.py b/src/calibre/gui2/metadata/single.py
index f39ae5668f..e254b711cc 100644
--- a/src/calibre/gui2/metadata/single.py
+++ b/src/calibre/gui2/metadata/single.py
@@ -322,7 +322,7 @@ class MetadataSingleDialogBase(ResizableDialog):
         pdfpath = self.formats_manager.get_format_path(self.db, self.book_id,
                                                        'pdf')
         from calibre.gui2.metadata.pdf_covers import PDFCovers
-        d = self.__pdf_covers = PDFCovers(pdfpath, parent=self)
+        d = PDFCovers(pdfpath, parent=self)
         if d.exec_() == d.Accepted:
             cpath = d.cover_path
             if cpath: