fx.NavigationRegistry = new (new Class({
  SelectedNavigationItem: null,
  FirstNavigationItem: null,
  
  setActiveItem: function(item)
  {
    if(this.SelectedNavigationItem != null)
    {
      this.SelectedNavigationItem.setMouseOut();
      this.SelectedNavigationItem.initEvents();
    }
    this.SelectedNavigationItem = item;
  },
  
  registerItem: function(item)
  {
    if(this.FirstNavigationItem == null)
    {
      this.FirstNavigationItem = item;
    }
  }
}));