Add a destroy_on_close flag to the base Window class.

enaml/widgets/window.py

@@ -2,7 +2,7 @@
 #  Copyright (c) 2012, Enthought, Inc.
 #  All rights reserved.
 #------------------------------------------------------------------------------
-from traits.api import Unicode, Enum, Property, Str, cached_property
+from traits.api import Unicode, Enum, Property, Str, Bool, cached_property
 
 from enaml.core.trait_types import EnamlEvent
 
@@ -33,6 +33,10 @@ class Window(Widget):
     #: value is 'non_modal'.
     modality = Enum('non_modal', 'application_modal', 'window_modal')
 
+    #: If this value is set to True, the window will be destroyed on
+    #: the completion of the `closed` event.
+    destroy_on_close = Bool(True)
+
     #: An event fired when the window is closed.
     closed = EnamlEvent
 
@@ -91,6 +95,8 @@ def on_action_closed(self, content):
 
         """
         self.closed()
+        if self.destroy_on_close:
+            self.destroy()
 
     #--------------------------------------------------------------------------
     # Public API