do not create a view more than once.

make it invisible rather than destroying it.
close #228

bauble/__init__.py

@@ -401,8 +401,8 @@ def main(uri=None):
     prefs.save()
 
     # set the default command handler
-    import bauble.view as view
-    pluginmgr.register_command(view.DefaultCommandHandler)
+    from bauble.view import DefaultCommandHandler
+    pluginmgr.register_command(DefaultCommandHandler)
 
     # now that we have a connection create the gui, start before the plugins
     # are initialized in case they have to do anything like add a menu

bauble/ui.py

@@ -355,16 +355,25 @@ def set_view(self, view=None):
         :param view: default=None
         '''
         view_box = self.widgets.view_box
+        must_add_this_view = True
         for kid in view_box.get_children():
-            view_box.remove(kid)
-        view_box.pack_start(view, True, True, 0)
+            if view == kid:
+                must_add_this_view = False
+                kid.set_visible(True)
+            else:
+                kid.set_visible(False)
+        if must_add_this_view:
+            view_box.pack_start(view, True, True, 0)
         view.show_all()
 
     def get_view(self):
         '''
         return the current view in the view box
         '''
-        return self.widgets.view_box.get_children()[0]
+        for kid in self.widgets.view_box.get_children():
+            if kid.get_visible():
+                return kid
+        return None
 
     def create_main_menu(self):
         """

bauble/view.py

@@ -1270,14 +1270,14 @@ class DefaultCommandHandler(pluginmgr.CommandHandler):
 
     def __init__(self):
         super(DefaultCommandHandler, self).__init__()
-        self.view = None
 
     command = [None]
+    view = None
 
     def get_view(self):
-        if self.view is None:
-            self.view = SearchView()
-        return self.view
+        if self.__class__.view is None:
+            self.__class__.view = SearchView()
+        return self.__class__.view
 
     def __call__(self, cmd, arg):
         self.view.search(arg)