Bug 156883 [Viewers] enhancements to ILazyTreeContentProvider
bundles/org.eclipse.jface/src/org/eclipse/jface/viewers/AbstractTreeViewer.java
if (reveal && newSelection.size() > 0) {
			showItem((Item) newSelection.get(0));
		}
	}
	/**
	 * Shows the given item.
	 * 
	 * @param item
	 *            the item
	 */
	protected abstract void showItem(Item item);
	/**
	 * Updates the tree items to correspond to the child elements of the given
	 * parent element. If null is passed for the children, this method obtains
	 * them (only if needed).
	 * 
	 * @param widget
	 *            the widget
	 * @param parent
	 *            the parent element
	 * @param elementChildren
	 *            the child elements, or null
	 * @deprecated this is no longer called by the framework
	 */
	protected void updateChildren(Widget widget, Object parent,
			Object[] elementChildren) {