Index: Tkinter.py
===================================================================
--- Tkinter.py	(revision 67259)
+++ Tkinter.py	(working copy)
@@ -177,8 +177,7 @@
         then the existing value is retained.
         """
         global _varnum
-        if not master:
-            master = _default_root
+        master = setup_master(master)
         self._master = master
         self._tk = master.tk
         if name:
@@ -323,7 +322,7 @@
 
 def mainloop(n=0):
     """Run the main loop of Tcl."""
-    _default_root.tk.mainloop(n)
+    setup_master().tk.mainloop(n)
 
 getint = int
 
@@ -331,7 +330,7 @@
 
 def getboolean(s):
     """Convert true and false to integer values 1 and 0."""
-    return _default_root.tk.getboolean(s)
+    return setup_master().tk.getboolean(s)
 
 # Methods defined on both toplevel and interior widgets
 class Misc:
@@ -1892,12 +1891,7 @@
     """Internal class."""
     def _setup(self, master, cnf):
         """Internal function. Sets up information about children."""
-        if _support_default_root:
-            global _default_root
-            if not master:
-                if not _default_root:
-                    _default_root = Tk()
-                master = _default_root
+        master = setup_master(master)
         self.master = master
         self.tk = master.tk
         name = None
@@ -3220,10 +3214,7 @@
     _last_id = 0
     def __init__(self, imgtype, name=None, cnf={}, master=None, **kw):
         self.name = None
-        if not master:
-            master = _default_root
-            if not master:
-                raise RuntimeError, 'Too early to create image'
+        master = setup_master(master)
         self.tk = master.tk
         if not name:
             Image._last_id += 1
@@ -3343,8 +3334,8 @@
         Valid resource names: background, data, file, foreground, maskdata, maskfile."""
         Image.__init__(self, 'bitmap', name, cnf, master, **kw)
 
-def image_names(): return _default_root.tk.call('image', 'names')
-def image_types(): return _default_root.tk.call('image', 'types')
+def image_names(): return setup_master().tk.call('image', 'names')
+def image_types(): return setup_master().tk.call('image', 'types')
 
 
 class Spinbox(Widget):