Читал, читал.

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There are two important things to note about this technique. First, it's powerful since now that you've subclassed the "real" Internet Explorer window, you can do almost anything you want. Second, it's really, really, really bad, and likely to get you in trouble if you aren't careful. Once you take over the Explorer window like this, all bets are off. Didn't your mother tell you that you're not supposed to subvert the browser? You're supposed to customize it through the official interfaces (IDocHostUIHandler)! But there's nothing like breaking the taboos to make your blood flow.

Paul DiLascia

Решайте сами.