Issue #10997: Prevent a duplicate entry in IDLE's "Recent Files" menu.

Lib/idlelib/EditorWindow.py

@@ -856,7 +856,7 @@ class EditorWindow(object):
         # for each edit window instance, construct the recent files menu
         for instance in self.top.instance_dict.keys():
             menu = instance.recent_files_menu
-            menu.delete(1, END)  # clear, and rebuild:
+            menu.delete(0, END)  # clear, and rebuild:
             for i, file_name in enumerate(rf_list):
                 file_name = file_name.rstrip()  # zap \n
                 # make unicode string to display non-ASCII chars correctly

Misc/NEWS

@@ -67,6 +67,8 @@ Core and Builtins
 Library
 -------
 
+- Issue #10997: Prevent a duplicate entry in IDLE's "Recent Files" menu.
+
 - Issue12510: Attempting to get invalid tooltip no longer closes Idle.
   Original patch by Roger Serwy.