diff -r 180f5bf7d1b9 Lib/idlelib/AutoCompleteWindow.py
--- a/Lib/idlelib/AutoCompleteWindow.py	Thu Sep 11 14:33:02 2014 +0300
+++ b/Lib/idlelib/AutoCompleteWindow.py	Sat Sep 13 17:03:10 2014 +0300
@@ -169,7 +169,7 @@
         self.lasttypedstart = self.start
 
         # Put widgets in place
-        self.autocompletewindow = acw = Toplevel(self.widget)
+        self.autocompletewindow = acw = Toplevel(self.widget, class_='Idle3')
         # Put it in a position so that it is not seen.
         acw.wm_geometry("+10000+10000")
         # Make it float
diff -r 180f5bf7d1b9 Lib/idlelib/PyShell.py
--- a/Lib/idlelib/PyShell.py	Thu Sep 11 14:33:02 2014 +0300
+++ b/Lib/idlelib/PyShell.py	Sat Sep 13 17:03:10 2014 +0300
@@ -626,7 +626,7 @@
             return
         item = RemoteObjectBrowser.StubObjectTreeItem(self.rpcclt, oid)
         from idlelib.TreeWidget import ScrolledCanvas, TreeNode
-        top = Toplevel(self.tkconsole.root)
+        top = Toplevel(self.tkconsole.root, class_='Idle3')
         theme = idleConf.GetOption('main','Theme','name')
         background = idleConf.GetHighlight(theme, 'normal')['background']
         sc = ScrolledCanvas(top, bg=background, highlightthickness=0)
@@ -1538,7 +1538,7 @@
     enable_edit = enable_edit or edit_start
     enable_shell = enable_shell or not enable_edit
     # start editor and/or shell windows:
-    root = Tk(className="Idle")
+    root = Tk(className="Idle3")
 
     # set application icon
     icondir = os.path.join(os.path.dirname(__file__), 'Icons')
diff -r 180f5bf7d1b9 Lib/idlelib/SearchDialogBase.py
--- a/Lib/idlelib/SearchDialogBase.py	Thu Sep 11 14:33:02 2014 +0300
+++ b/Lib/idlelib/SearchDialogBase.py	Sat Sep 13 17:03:10 2014 +0300
@@ -72,7 +72,7 @@
         Other dialogs override subsidiary create_x methods as needed.
         Replace and Find-in-Files add another entry row.
         '''
-        top = Toplevel(self.root)
+        top = Toplevel(self.root, class_='Idle3')
         top.bind("<Return>", self.default_command)
         top.bind("<Escape>", self.close)
         top.protocol("WM_DELETE_WINDOW", self.close)
diff -r 180f5bf7d1b9 Lib/idlelib/StackViewer.py
--- a/Lib/idlelib/StackViewer.py	Thu Sep 11 14:33:02 2014 +0300
+++ b/Lib/idlelib/StackViewer.py	Sat Sep 13 17:03:10 2014 +0300
@@ -11,7 +11,7 @@
 def StackBrowser(root, flist=None, tb=None, top=None):
     if top is None:
         from tkinter import Toplevel
-        top = Toplevel(root)
+        top = Toplevel(root, class_='Idle3')
     sc = ScrolledCanvas(top, bg="white", highlightthickness=0)
     sc.frame.pack(expand=1, fill="both")
     item = StackTreeItem(flist, tb)
diff -r 180f5bf7d1b9 Lib/idlelib/WindowList.py
--- a/Lib/idlelib/WindowList.py	Thu Sep 11 14:33:02 2014 +0300
+++ b/Lib/idlelib/WindowList.py	Sat Sep 13 17:03:10 2014 +0300
@@ -1,5 +1,7 @@
 from tkinter import *
 
+WM_CLASS = 'Idle3'
+
 class WindowList:
 
     def __init__(self):
@@ -58,6 +60,8 @@
 class ListedToplevel(Toplevel):
 
     def __init__(self, master, **kw):
+        kw['class'] = 'Idle3'
+        kw.pop('class_', None)
         Toplevel.__init__(self, master, kw)
         registry.add(self)
         self.focused_widget = self
diff -r 180f5bf7d1b9 Lib/idlelib/aboutDialog.py
--- a/Lib/idlelib/aboutDialog.py	Thu Sep 11 14:33:02 2014 +0300
+++ b/Lib/idlelib/aboutDialog.py	Sat Sep 13 17:03:10 2014 +0300
@@ -16,7 +16,7 @@
         """
         _htest - bool, change box location when running htest
         """
-        Toplevel.__init__(self, parent)
+        Toplevel.__init__(self, parent, class_='Idle3')
         self.configure(borderwidth=5)
         # place dialog below parent if running htest
         self.geometry("+%d+%d" % (
diff -r 180f5bf7d1b9 Lib/idlelib/configDialog.py
--- a/Lib/idlelib/configDialog.py	Thu Sep 11 14:33:02 2014 +0300
+++ b/Lib/idlelib/configDialog.py	Sat Sep 13 17:03:10 2014 +0300
@@ -29,7 +29,7 @@
         _htest - bool, change box location when running htest
         _utest - bool, don't wait_window when running unittest
         """
-        Toplevel.__init__(self, parent)
+        Toplevel.__init__(self, parent, class_='Idle3')
         self.parent = parent
         if _htest:
             parent.instance_dict = {}
diff -r 180f5bf7d1b9 Lib/idlelib/configHelpSourceEdit.py
--- a/Lib/idlelib/configHelpSourceEdit.py	Thu Sep 11 14:33:02 2014 +0300
+++ b/Lib/idlelib/configHelpSourceEdit.py	Sat Sep 13 17:03:10 2014 +0300
@@ -17,7 +17,7 @@
 
         _htest - bool, change box location when running htest
         """
-        Toplevel.__init__(self, parent)
+        Toplevel.__init__(self, parent, class_='Idle3')
         self.configure(borderwidth=5)
         self.resizable(height=FALSE, width=FALSE)
         self.title(title)
diff -r 180f5bf7d1b9 Lib/idlelib/configSectionNameDialog.py
--- a/Lib/idlelib/configSectionNameDialog.py	Thu Sep 11 14:33:02 2014 +0300
+++ b/Lib/idlelib/configSectionNameDialog.py	Sat Sep 13 17:03:10 2014 +0300
@@ -14,7 +14,7 @@
         used_names - string collection, names already in use for validity check
         _htest - bool, change box location when running htest
         """
-        Toplevel.__init__(self, parent)
+        Toplevel.__init__(self, parent, class_='Idle3')
         self.configure(borderwidth=5)
         self.resizable(height=FALSE, width=FALSE)
         self.title(title)
diff -r 180f5bf7d1b9 Lib/idlelib/keybindingDialog.py
--- a/Lib/idlelib/keybindingDialog.py	Thu Sep 11 14:33:02 2014 +0300
+++ b/Lib/idlelib/keybindingDialog.py	Sat Sep 13 17:03:10 2014 +0300
@@ -15,7 +15,7 @@
                  to virtual events, for overlap checking
         _htest - bool, change box location when running htest
         """
-        Toplevel.__init__(self, parent)
+        Toplevel.__init__(self, parent, class_='Idle3')
         self.configure(borderwidth=5)
         self.resizable(height=FALSE,width=FALSE)
         self.title(title)
diff -r 180f5bf7d1b9 Lib/idlelib/textView.py
--- a/Lib/idlelib/textView.py	Thu Sep 11 14:33:02 2014 +0300
+++ b/Lib/idlelib/textView.py	Sat Sep 13 17:03:10 2014 +0300
@@ -18,7 +18,7 @@
 
         _htest - bool; change box location when running htest.
         """
-        Toplevel.__init__(self, parent)
+        Toplevel.__init__(self, parent, class_='Idle3')
         self.configure(borderwidth=5)
         # place dialog below parent if running htest
         self.geometry("=%dx%d+%d+%d" % (625, 500,