Swong, you seem to have a totally different issue than in the rest of this thread - I only see text in your button, no icon.
Can you post how you are using this cell? The code looks like it should work, but without knowing roughly what your application does with it, it is hard to say what else could be wrong. You say that the "Cancel" text does nothing, but from what you've wired up, it *should* do nothing - there is no event hander, nor is it event drawn on the page.
Ideally, please post a full working example implementing EntryPoint, or modify one of the example entrypoints at http://sencha.com/examples/.