diff --git a/setup/extensions.py b/setup/extensions.py
index 74ff5a88db..231aae4ee6 100644
--- a/setup/extensions.py
+++ b/setup/extensions.py
@@ -90,7 +90,7 @@ extensions = [
         ),
 
     Extension('_patiencediff_c',
-        ['calibre/utils/diff/_patiencediff_c.c'],
+        ['calibre/gui2/tweak_book/diff/_patiencediff_c.c'],
         ),
 
     Extension('icu',
diff --git a/src/calibre/utils/diff/__init__.py b/src/calibre/gui2/tweak_book/diff/__init__.py
similarity index 100%
rename from src/calibre/utils/diff/__init__.py
rename to src/calibre/gui2/tweak_book/diff/__init__.py
diff --git a/src/calibre/utils/diff/_patiencediff_c.c b/src/calibre/gui2/tweak_book/diff/_patiencediff_c.c
similarity index 100%
rename from src/calibre/utils/diff/_patiencediff_c.c
rename to src/calibre/gui2/tweak_book/diff/_patiencediff_c.c
diff --git a/src/calibre/gui2/tweak_book/diff/main.py b/src/calibre/gui2/tweak_book/diff/main.py
new file mode 100644
index 0000000000..3adfa10d58
--- /dev/null
+++ b/src/calibre/gui2/tweak_book/diff/main.py
@@ -0,0 +1,10 @@
+#!/usr/bin/env python
+# vim:fileencoding=utf-8
+from __future__ import (unicode_literals, division, absolute_import,
+                        print_function)
+
+__license__ = 'GPL v3'
+__copyright__ = '2014, Kovid Goyal <kovid at kovidgoyal.net>'
+
+
+
diff --git a/src/calibre/gui2/tweak_book/diff.py b/src/calibre/gui2/tweak_book/diff/view.py
similarity index 100%
rename from src/calibre/gui2/tweak_book/diff.py
rename to src/calibre/gui2/tweak_book/diff/view.py