Prevent toplevel wx windows from being destroyed on close.

Update the Window class to toggle visibility to False when closed.

enaml/widgets/window.py

@@ -94,6 +94,7 @@ def on_action_closed(self, content):
         """ Handle the 'closed' action from the client widget.
 
         """
+        self.set_guarded(visible=False)
         self.closed()
         if self.destroy_on_close:
             self.destroy()

enaml/wx/wx_main_window.py

@@ -103,6 +103,7 @@ def __init__(self, *args, **kwargs):
         self._tool_bars = None
         self._batch = False
         self.Bind(wx.EVT_MENU, self.OnMenu)
+        self.Bind(wx.EVT_CLOSE, self.OnClose)
         self.Bind(aui.EVT_AUI_PANE_CLOSE, self.OnPaneClose)
         self.Bind(aui.EVT_AUI_PANE_FLOATED, self.OnPaneFloated)
         self.Bind(aui.EVT_AUI_PANE_DOCKED, self.OnPaneDocked)
@@ -160,6 +161,15 @@ def OnMenu(self, event):
                 action.SetChecked(event.Checked())
             action.Trigger()
 
+    def OnClose(self, event):
+        """ The event handler for the EVT_CLOSE event.
+
+        This event handler prevents the frame from being destroyed on
+        close. Instead it just sets the visibility to False.
+
+        """
+        self.Hide()
+
     #--------------------------------------------------------------------------
     # Public API
     #--------------------------------------------------------------------------

enaml/wx/wx_window.py

@@ -32,6 +32,7 @@ def __init__(self, *args, **kwargs):
         self._central_widget = None
         self.SetSizer(wxSingleWidgetSizer())
         self.Bind(wx.EVT_MENU, self.OnMenu)
+        self.Bind(wx.EVT_CLOSE, self.OnClose)
 
     #--------------------------------------------------------------------------
     # Event Handlers
@@ -49,6 +50,15 @@ def OnMenu(self, event):
                 action.SetChecked(event.Checked())
             action.Trigger()
 
+    def OnClose(self, event):
+        """ The event handler for the EVT_CLOSE event.
+
+        This event handler prevents the frame from being destroyed on
+        close. Instead it just sets the visibility to False.
+
+        """
+        self.Hide()
+
     #--------------------------------------------------------------------------
     # Public API
     #--------------------------------------------------------------------------