Fix SF bug #763637, 2.3b2 unpack tuple of wrong size in after_cancel

Tk 8.4 may return different values than 8.3.  This fix should handle
either version.

Lib/lib-tk/Tkinter.py

@@ -475,8 +475,10 @@ def after_cancel(self, id):
         Identifier returned by after or after_idle must be
         given as first parameter."""
         try:
-            (script, type) = self.tk.splitlist(
-                self.tk.call('after', 'info', id))
+            data = self.tk.call('after', 'info', id)
+            # In Tk 8.3, splitlist returns: (script, type)
+            # In Tk 8.4, splitlist may return (script, type) or (script,)
+            script = self.tk.splitlist(data)[0]
             self.deletecommand(script)
         except TclError:
             pass

Misc/NEWS

@@ -30,6 +30,9 @@ Library
 - SF bug 763023: fix uncaught ZeroDivisionError in difflib ratio methods
   when there are no lines.
 
+- SF bug 763637: fix exception in Tkinter with after_cancel
+  which could occur with Tk 8.4
+
 Tools/Demos
 -----------