saving arraylist in application settings winforms

I am writing a simple application - a kind of saper game in winforms in C#. My application already saves some information in application settings like the size or colour of buttons , but when i try to save an arraylist of my own structure I get a problem. The are no errors but the information is not saved for the next program execution.Ustawienia is a public static class including wyniki which is another form , and Properties.Settings.Default.scores is an ArrayList added in application settigs. I would be grateful if you have any idea what i am doing wrong and how to store the arraylist in app settings.

Here is the code:

public partial class Form3 : Form {

    public Form3()
    {
        InitializeComponent();
        if (Properties.Settings.Default.scores == null)
            Properties.Settings.Default.scores = new System.Collections.ArrayList();

    }

    private void ok_click(object sender, EventArgs e)
    {

       Highscore higscore = new Highscore(Properties.Settings.Default.ktory, textBox1.Text, ustawienia.ile_wierszy, ustawienia.ile_kolumn, ustawienia.elapsed.Seconds);
       Properties.Settings.Default.scores.Add( higscore);

       Properties.Settings.Default.scores.Sort(new myComparer());

       Properties.Settings.Default.ktory++;
       Properties.Settings.Default.Save();
       Highscore.show();
       this.Close();

    }

}
public class Highscore
{
   public int nubmer;//w properties ktory=+1;
   public string name;
    int rows;
    int columns;
   public int time;
    public Highscore(int _number, string _name, int _rows, int _columns, int _time)
    {
        number = _number;
        name = _name;
        rows = _rows;
        columns = _columns;
        time = _time;
    }
    public static void show()
    {
          ListView list = (ListView)ustawienia.wyniki.Controls.Find("listView1", true)[0];
          list.Items.Clear();
        foreach (Highscore e in Properties.Settings.Default.scores)
        {

            ListViewItem newItem = new ListViewItem(new[] { e.name, e.time.ToString(), e.rows.ToString()+"x"+e.columns.ToString() });
            lista.Items.Add(newItem);
        }

        ustawienia.wyniki.Show();
    }
}
public class myComparer:IComparer
{

int IComparer.Compare(Object x, Object y)
{
    if (((Highscore)x).time < ((Highscore)y).time)
        return 1;
    else if   (((Highscore)x).time > ((Highscore)y).time)
        return -1;
    else
    {

            return String.Compare(((Highscore)x).name,((Highscore)y).name);
    }
}
}

}