diff --git a/Lib/idlelib/config.py b/Lib/idlelib/config.py
index 82afd6c49269d2d..01c2eec6e678176 100644
--- a/Lib/idlelib/config.py
+++ b/Lib/idlelib/config.py
@@ -28,6 +28,7 @@
 from configparser import ConfigParser
 import os
 import sys
+import re
 
 from tkinter.font import Font
 import idlelib
@@ -587,6 +588,15 @@ def GetCurrentKeySet(self):
                 v2 = [ x.replace('<Alt-', '<Option-') for x in v ]
                 if v != v2:
                     result[k] = v2
+        else:
+            def replace(m):
+                return m.group('prefix') + m.group('alpha').swapcase()+'>'
+
+            pat = '(?P<prefix><[A-Za-z-]+Key-)(?P<alpha>[a-zA-Z])>'
+            for k, v in result.items():
+                v2 = [re.sub(pat, replace, x) for x in v]
+                if v != v2:
+                    v.extend(v2)
 
         return result
 
diff --git a/Lib/idlelib/idle_test/test_config.py b/Lib/idlelib/idle_test/test_config.py
index 6d75cf7aa67dcce..e9702a2d511a3b3 100644
--- a/Lib/idlelib/idle_test/test_config.py
+++ b/Lib/idlelib/idle_test/test_config.py
@@ -488,23 +488,6 @@ def test_get_keybinding(self):
         eq(conf.GetKeyBinding('NOT EXISTS', '<<copy>>'), [])
         eq(conf.GetKeyBinding('IDLE Modern Unix', 'NOT EXISTS'), [])
 
-    def test_get_current_keyset(self):
-        current_platform = sys.platform
-        conf = self.mock_config()
-
-        # Ensure that platform isn't darwin
-        sys.platform = 'some-linux'
-        self.assertEqual(conf.GetCurrentKeySet(), conf.GetKeySet(conf.CurrentKeys()))
-
-        # This should not be the same, since replace <Alt- to <Option-.
-        # Above depended on config-extensions.def having Alt keys,
-        # which is no longer true.
-        # sys.platform = 'darwin'
-        # self.assertNotEqual(conf.GetCurrentKeySet(), conf.GetKeySet(conf.CurrentKeys()))
-
-        # Restore platform
-        sys.platform = current_platform
-
     def test_get_keyset(self):
         conf = self.mock_config()