Issue *24750: Switch all scrollbars in IDLE to ttk versions.

Where needed, add minimal tests to cover changes.

Lib/idlelib/idle_test/test_config_key.py

@@ -0,0 +1,31 @@
+''' Test idlelib.config_key.
+
+Coverage: 56%
+'''
+from idlelib import config_key
+from test.support import requires
+requires('gui')
+import unittest
+from tkinter import Tk, Text
+
+
+class GetKeysTest(unittest.TestCase):
+
+    @classmethod
+    def setUpClass(cls):
+        cls.root = Tk()
+
+    @classmethod
+    def tearDownClass(cls):
+        cls.root.destroy()
+        del cls.root
+
+
+    def test_init(self):
+        dia = config_key.GetKeysDialog(
+            self.root, 'test', '<<Test>>', ['<Key-F12>'], _utest=True)
+        dia.Cancel()
+
+
+if __name__ == '__main__':
+    unittest.main(verbosity=2)