Text field not responding

I'm quite new to cocoa touch and have been playing around with it for a few days now. I'm testing some examples from Apress book on simulator and one of it requires to create textfield. The problem is, textfield is not responding at all and doesn't show up keyboard as a result. Anyone know 开发者_高级运维what could be the culprit? I've checked "User interaction enable" and it is checked.

OS = snow leopard ios = 4.2

Edit : Not just textbox, all controls don't respond at all.

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Ok I've just found out the culprit. Although I set "User Interaction enabled" of all the controls, I've missed the one from "view" object itself. Hope this help to whoever have the same problem.