/// <summary>
/// Focus the first item in the TreeView.
/// </summary>
/// <returns>A value indicating whether the item was focused.</returns>
private bool FocusFirstItem()
{
// Get the first item in the TreeView.
TreeViewItem item = ItemContainerGenerator.ContainerFromIndex(0) as TreeViewItem;
return((item != null) ?
(item.IsEnabled && item.Focus()) || item.FocusDown() :
false);
}
