Tkinter, step 2: adapt imports.
diff --git a/Lib/idlelib/ReplaceDialog.py b/Lib/idlelib/ReplaceDialog.py
index 2d6c802..d713e61 100644
--- a/Lib/idlelib/ReplaceDialog.py
+++ b/Lib/idlelib/ReplaceDialog.py
@@ -1,4 +1,4 @@
-from Tkinter import *
+from tkinter import *
 
 from idlelib import SearchEngine
 from idlelib.SearchDialogBase import SearchDialogBase