/// <summary>
/// Add item
/// </summary>
/// <param name="item">item to add</param>
private void AddItem(ActionableObject item)
{
if (!item.IsActive)
{
if (this.last == null)
{
this.first = item;
this.last = item;
}
else
{
this.last.Next = item;
}
item.IsActive = true;
}
}