ExtJS 4 MVC multiple instances of views and sub/child controller difficulties

Question

I have encountered a problem with the MVC pattern in ExtJS 4. At least, I think I have. Having approached multiple people with this question, and having posted numerous times in

Answer 1

I don't think you ever need more than 1 instance of a controller, regardless of how many views/models you have. See functional example here:

http://whatisextjs.com/extjs-4-extension/fieldset-w-dynamic-controls-7