Bug 305739 [viewers] #expandToLevel(Object, level) retrieves all children when virtual
bundles/org.eclipse.jface/src/org/eclipse/jface/viewers/AbstractTreeViewer.java
if (widgets.length == 0) {
			return;
		}
		for (int i = 0; i < widgets.length; i++) {
			internalAdd(widgets[i], parentElementOrTreePath, childElements);
		}
	}
	/**
	 * Find the items for the given element of tree path
	 *
	 * @param parentElementOrTreePath
	 *            the element or tree path
	 * @return the items for that element
	 *
	 * @since 3.3
	 */
	final protected Widget[] internalFindItems(Object parentElementOrTreePath) {
		Widget[] widgets;
		if (parentElementOrTreePath instanceof TreePath) {
			TreePath path = (TreePath) parentElementOrTreePath;
			Widget w = internalFindItem(path);
			if (w == null) {
				widgets = new Widget[] {};
			} else {
				widgets = new Widget[] { w };
			}
		} else {
			widgets = findItems(parentElementOrTreePath);
		}