Bug 305739 [viewers] #expandToLevel(Object, level) retrieves all children when virtual
bundles/org.eclipse.jface/src/org/eclipse/jface/viewers/TreeViewer.java
*
	 * @see org.eclipse.jface.viewers.AbstractTreeViewer#internalInitializeTree(org.eclipse.swt.widgets.Control)
	 */
	protected void internalInitializeTree(Control widget) {
		if (contentProviderIsLazy) {
			if (widget instanceof Tree && widget.getData() != null) {
				virtualLazyUpdateChildCount(widget, 0);
				return;
			}
		}
		super.internalInitializeTree(tree);
	}
	/*
	 * (non-Javadoc)
	 *
	 * @see org.eclipse.jface.viewers.AbstractTreeViewer#updatePlus(org.eclipse.swt.widgets.Item,
	 *      java.lang.Object)
	 */
	protected void updatePlus(Item item, Object element) {
		if (contentProviderIsLazy) {
			Object data = item.getData();
			int itemCount = 0;
			if (data != null) {
				
				itemCount = ((TreeItem) item).getItemCount();
			}
			virtualLazyUpdateHasChildren(item, itemCount);
		} else {
			super.updatePlus(item, element);
		}