/// <summary>
/// Gets all the <see cref="ElementViewModel"/> instances that are directly contained in this <see cref="ElementViewModel"/> instance.
/// </summary>
/// <returns>
/// </returns>
protected override IEnumerable <ElementViewModel> GetAllChildElements()
{
var leaf = base.GetAllChildElements();
var contained = thisElementCollection
.OfType <ConfigurationElement>()
.Select(x => new { Browasble = TypeDescriptor.GetAttributes(x).OfType <BrowsableAttribute>().FirstOrDefault(), Instance = x })
.Where(x => x.Browasble == null || x.Browasble.Browsable)
.Select(x => ContainingSection.CreateCollectionElement(this, x.Instance))
.Cast <ElementViewModel>();
return(leaf.Union(contained));
}