Bug 305739 [viewers] #expandToLevel(Object, level) retrieves all children when virtual
bundles/org.eclipse.jface/src/org/eclipse/jface/viewers/AbstractTreeViewer.java
* <p>
	 * This method should be called (by the content provider) when elements have
	 * been added to the model, in order to cause the viewer to accurately
	 * reflect the model. This method only affects the viewer, not the model.
	 * </p>
	 *
	 * @param parentElementOrTreePath
	 *            the parent element, or the tree path to the parent
	 * @param element
	 *            the element
	 * @param position
	 *            a 0-based position relative to the model, or -1 to indicate
	 *            the last position
	 *
	 * @since 3.2
	 */
	public void insert(Object parentElementOrTreePath, Object element,
			int position) {
		Assert.isNotNull(parentElementOrTreePath);
		Assert.isNotNull(element);
		if (checkBusy())
			return;
		if (getComparator() != null || hasFilters()) {
			add(parentElementOrTreePath, new Object[] { element });
			return;
		}
		Widget[] items;
		if (internalIsInputOrEmptyPath(parentElementOrTreePath)) {
			items = new Widget[] { getControl() };
		} else {