It's not obvious when 'Customize View' is applied

After several hours of trying to figure out why a folder didn't show certain messages, I realised that I had selected a Custom View a few days ago and it still applied quietly when I selected that folder. This is not the first time I fall for it. Is there a way TB would show that a Custom View filtered out some of the messages? Eg the Custom View button could be depressed, or the background in the messages pane would be different, or something. As it is now, I think I won't use the feature again and save myself hours of scratching my head in the future.