diff -r 57280a01aecf Lib/idlelib/EditorWindow.py
--- Lib/idlelib/EditorWindow.py	Thu Jan 27 21:38:46 2011 +0100
+++ Lib/idlelib/EditorWindow.py	Fri Jan 28 15:31:17 2011 -0800
@@ -1546,7 +1546,12 @@
 
 def get_accelerator(keydefs, eventname):
     keylist = keydefs.get(eventname)
-    if not keylist:
+    # issue10940: temporary workaround to prevent hang with OS X Cocoa Tk 8.5
+    # if not keylist:
+    if (not keylist) or (macosxSupport.runningAsOSXApp() and eventname in {
+                            "<<open-module>>",
+                            "<<goto-line>>",
+                            "<<change-indentwidth>>"}):
         return ""
     s = keylist[0]
     s = re.sub(r"-[a-z]\b", lambda m: m.group().upper(), s)