diff -r 3a923156ca05 Lib/tkinter/__init__.py
--- a/Lib/tkinter/__init__.py	Mon Jun 02 21:32:49 2014 +0300
+++ b/Lib/tkinter/__init__.py	Mon Jun 02 23:12:41 2014 +0300
@@ -41,7 +41,7 @@
 import re
 
 
-wantobjects = 1
+wantobjects = 0
 
 TkVersion = float(_tkinter.TK_VERSION)
 TclVersion = float(_tkinter.TCL_VERSION)
@@ -2875,10 +2875,16 @@
         relief, repeatdelay, repeatinterval, takefocus,
         troughcolor, width."""
         Widget.__init__(self, master, 'scrollbar', cnf, kw)
-    def activate(self, index):
-        """Display the element at INDEX with activebackground and activerelief.
-        INDEX can be "arrow1","slider" or "arrow2"."""
-        self.tk.call(self._w, 'activate', index)
+    def activate(self, element=None, *, index=None):
+        """If element is not None and is one of "arrow1", "slider" or "arrow2"
+        then it is marked as active. Otherwise the current active element is
+        returned, or None is returned in case no element is active."""
+        if index is not None:
+            warnings.warn("The 'index' keyword argument is deprecated and "
+                          "will be removed in 3.6. Use 'element' instead.",
+                          DeprecationWarning, 2)
+            element = index
+        return self.tk.call(self._w, 'activate', element) or None
     def delta(self, deltax, deltay):
         """Return the fractional change of the scrollbar setting if it
         would be moved by DELTAX or DELTAY pixels."""
@@ -2896,10 +2902,10 @@
         """Return the current fractional values (upper and lower end)
         of the slider position."""
         return self._getdoubles(self.tk.call(self._w, 'get'))
-    def set(self, *args):
+    def set(self, first, last):
         """Set the fractional values of the slider position (upper and
         lower ends as value between 0 and 1)."""
-        self.tk.call((self._w, 'set') + args)
+        self.tk.call(self._w, 'set', first, last)
 
 
 
diff -r 3a923156ca05 Lib/tkinter/test/test_tkinter/test_widgets.py
--- a/Lib/tkinter/test/test_tkinter/test_widgets.py	Mon Jun 02 21:32:49 2014 +0300
+++ b/Lib/tkinter/test/test_tkinter/test_widgets.py	Mon Jun 02 23:12:41 2014 +0300
@@ -916,6 +916,25 @@
         self.checkEnumParam(widget, 'orient', 'vertical', 'horizontal',
                 errmsg='bad orientation "{}": must be vertical or horizontal')
 
+    def test_activate(self):
+        sb = self.create()
+        for e in ('arrow1', 'slider', 'arrow2'):
+            sb.activate(e)
+            self.assertEqual(sb.activate(), e)
+        sb.activate('')
+        self.assertIsNone(sb.activate())
+        self.assertRaises(TypeError, sb.activate, 'arrow1', 'arrow2')
+
+    def test_set(self):
+        sb = self.create()
+        sb.set(0.2, 0.4)
+        self.assertEqual(sb.get(), (0.2, 0.4))
+        self.assertRaises(TclError, sb.set, 'abc', 'def')
+        self.assertRaises(TclError, sb.set, 0.6, 'def')
+        self.assertRaises(TclError, sb.set, 0.6, None)
+        self.assertRaises(TypeError, sb.set, 0.6)
+        self.assertRaises(TypeError, sb.set, 0.6, 0.7, 0.8)
+
 
 @add_standard_options(StandardOptionsTests)
 class PanedWindowTest(AbstractWidgetTest, unittest.TestCase):