diff -r 5c9904f8ae60 Lib/idlelib/PyShell.py
--- a/Lib/idlelib/PyShell.py	Mon Jan 27 11:27:51 2014 +0200
+++ b/Lib/idlelib/PyShell.py	Mon Jan 27 12:07:06 2014 +0200
@@ -1529,6 +1529,11 @@
     enable_shell = enable_shell or not enable_edit
     # start editor and/or shell windows:
     root = Tk(className="Idle")
+    # set application icon
+    if TkVersion >= 8.5:
+        iconfile = os.path.join(os.path.dirname(__file__),
+                                'Icons', 'python.gif')
+        root.wm_iconphoto(True, PhotoImage(file=iconfile))
 
     fixwordbreaks(root)
     root.withdraw()