>On the first WebBrowser.Navigate() call I do, the HTML page is displayed ok. But, if I issue another Navigate() on the same control, I see that it inserts a right margin. How can I avoid that?

Ok, I have found the reason. I have some margins defined in the BODY of the page. For some kind of reason, this loads ok on the first time. But, when the page refreshes itself, it was causing a margin. I adjusted the margin in the BODY to make sure this won't happen.