When i'm adding a button to the page using the following code there is
some margin. i'm using GWT 2.4.0

import com.google.gwt.core.client.EntryPoint;
import com.google.gwt.user.client.ui.Button;
import com.google.gwt.user.client.ui.RootPanel;

public class GWTApplication implements EntryPoint {
public void onModuleLoad() {
RootPanel.get().add(new Button("Button"));
}
}


i don't want the margin in the web page.
it's also applied for when i'm testing ext-gwt sample pages.
Please help me.

Thank you.