Applet che mi apre 2 volte una pagina web invece di una o_O

[Dreamer89]

Salve. Utilizzando il metodo showDocument di AppletContext specificando come secondo parametro la stringa "_blank", mi si dovrebbe aprire la pagina web specificata su una nuova finestra, ma il problema è che me la apre ben 2 volte! o_O

import java.net.MalformedURLException;
import java.net.URL;
import java.util.HashMap;
import java.util.ArrayList;
import java.awt.BorderLayout;
import java.applet.AppletContext;
import javax.swing.JApplet;
import javax.swing.JLabel;
import javax.swing.JList;
import javax.swing.JScrollPane;
import javax.swing.event.ListSelectionEvent;
import javax.swing.event.ListSelectionListener;

public class SiteSelector extends JApplet
{
	private HashMap < Object, URL > sites;
	private ArrayList < String > siteNames;
	private JList siteChooser;
	
	public void init()
	{
		sites = new HashMap < Object, URL >();
		siteNames = new ArrayList < String >();
		
		getSitesFromHTMLParameters();
		
		add (new JLabel ("Choose a site to browse"), BorderLayout.NORTH);
		
		siteChooser = new JList (siteNames.toArray());
		siteChooser.addListSelectionListener
		(
			new ListSelectionListener()
			{
				public void valueChanged (ListSelectionEvent event)
				{
					Object object = siteChooser.getSelectedValue();
					
					URL newDocument = sites.get (object);
					
					AppletContext browser = getAppletContext();
					
					browser.showDocument (newDocument, "_blank");
				}
			}
		);
		
		add (new JScrollPane (siteChooser), BorderLayout.CENTER);
	}
	
	private void getSitesFromHTMLParameters()
	{
		String title;
		String location;
		URL url;
		int counter = 0;
		
		title = getParameter ("title" + counter);
		
		while (title != null)
		{
			location = getParameter ("location" + counter);
			
			try
			{
				url = new URL (location);
				sites.put (title, url);
				siteNames.add (title);
			}
			catch (MalformedURLException exception)
			{
				exception.printStackTrace();
			}
			
			counter++;
			title = getParameter ("title" + counter);
		}
	}
}

Qualche idea?