Tkinter, step 2: adapt imports.
diff --git a/Lib/idlelib/OutputWindow.py b/Lib/idlelib/OutputWindow.py
index 42aa77e..0782eaf 100644
--- a/Lib/idlelib/OutputWindow.py
+++ b/Lib/idlelib/OutputWindow.py
@@ -1,7 +1,7 @@
-from Tkinter import *
+from tkinter import *
 from idlelib.EditorWindow import EditorWindow
 import re
-import tkMessageBox
+import tkinter.messagebox as tkMessageBox
 from idlelib import IOBinding
 
 class OutputWindow(EditorWindow):