Index: Lib/idlelib/EditorWindow.py
===================================================================
--- Lib/idlelib/EditorWindow.py	(revision 71778)
+++ Lib/idlelib/EditorWindow.py	(working copy)
@@ -22,6 +22,17 @@
 # The default tab setting for a Text widget, in average-width characters.
 TK_TABWIDTH_DEFAULT = 8
 
+def _sys_version_info():
+    """Format sys.version_info according to how the version in htmlhelp
+    is set according to Python's sphinx configuration."""
+    major, minor, micro, level, serial = sys.version_info
+    release = '%s%s' % (major, minor)
+    if micro:
+        release += '%s' % micro
+    if level != 'final':
+        release += '%s%s' % (level[0], serial)
+    return release
+
 def _find_module(fullname, path=None):
     """Version of imp.find_module() that handles hierarchical module names"""
 
@@ -64,7 +75,7 @@
                                            'Doc', 'index.html')
             elif sys.platform[:3] == 'win':
                 chmfile = os.path.join(sys.prefix, 'Doc',
-                                       'Python%d%d.chm' % sys.version_info[:2])
+                                       'Python%s.chm' % _sys_version_info())
                 if os.path.isfile(chmfile):
                     dochome = chmfile