bug 9934; fix error when 'Manage Family Tree' is closed via ESC

or the dialog close 'x' in top left

gramps/gui/dbman.py

@@ -484,7 +484,8 @@ class DbManager(CLIDbManager, ManagedWindow):
             else:
                 del self.selection
                 del self.name_renderer
-                self.close()
+                if value != Gtk.ResponseType.DELETE_EVENT:
+                    self.close()
                 return None
 
     def __ask_to_break_lock(self, store, node):