Prevent activation of view UI when no database is loaded

svn: r16106

src/gui/viewmanager.py

@@ -1127,6 +1127,9 @@ class ViewManager(CLIManager):
         """
         Perform necessary actions when a page is changed.
         """
+        if not self.dbstate.open:
+            return
+
         self.__disconnect_previous_page()
         
         self.active_page = self.pages[page_num]