<StackPanel x:Name="LogViewerPanel" VerticalAlignment="Bottom" HorizontalAlignment="Center" Opacity="0.495">
		<Expander Header="Log Window" ExpandDirection="Up" Width="400">
		<ListBox x:Name="LogViewerListBox" Width="Auto" MinHeight="200" MaxHeight="200" MinWidth="400" />
		</Expander>
    </StackPanel> 

public void LogMessage(string message)
    {
        ListBox logger = guiRoot.FindName<ListBox>("LogViewerListBox");
        var item = new TextBlock(message);
        item.SetOpacity(1f);
        Brush brush = new SolidColorBrush(Noesis.Color.Yellow);
        item.SetForeground(brush);
        logger.GetItems().Insert(0, item);
    }

public void LogMessage(string message)
{
    TextBlock item = new TextBlock(message);
    item.SetOpacity(1f);
    item.SetForeground(Brushes.Yellow());
    this._messageList.Insert(0, item);

    ItemCollection items = this._logger.GetItems();
    items.Clear();
    foreach (TextBlock tb in this._messageList)
    {
        items.Add(tb);
    }
}