Bug 89137 [JFace] - API Review - "temporary" API in AbstractTreeViewer
AbstractTreeViewer contains two methods documented as "temporary" internalRefresh(Widget, Object) internalAdd(Widget, Object, Object [])
bundles/org.eclipse.jface/src/org/eclipse/jface/viewers/StructuredViewer.java
* Subclasses do not typically override this method, but implement
	 * <code>setSelectionToWidget(List, boolean)</code> instead.
	 * 
	 * @param selection
	 *            an IStructuredSelection of elements
	 * @param reveal
	 *            <code>true</code> to reveal the first element in the
	 *            selection, or <code>false</code> otherwise
	 */
	protected void setSelectionToWidget(ISelection selection, boolean reveal) {
		if (selection instanceof IStructuredSelection)
			setSelectionToWidget(((IStructuredSelection) selection).toList(), reveal);
		else
			setSelectionToWidget((List) null, reveal);
	}
	/**
	 * Sets this viewer's sorter and triggers refiltering and resorting of this
	 * viewer's element. Passing <code>null</code> turns sorting off.
	 * 
	 * @param sorter
	 *            a viewer sorter, or <code>null</code> if none
	 */
	public void setSorter(ViewerSorter sorter) {
		if (this.sorter != sorter) {
			this.sorter = sorter;
			refresh();
		}
	}
	/**
	 * Configures whether this structured viewer uses an internal hash table to