Bug 126061 [Viewers] Need to document that virtual tables and trees ignore sorters and filters
bundles/org.eclipse.jface/src/org/eclipse/jface/viewers/TreeViewer.java
if (index < tree.getItemCount()) {
				updateItem(tree.getItem(index), element);
			}
		} else {
			Widget[] parentItems = findItems(parent);
			for (int i = 0; i < parentItems.length; i++) {
				TreeItem parentItem = (TreeItem) parentItems[i];
				if (index < parentItem.getItemCount()) {
					updateItem(parentItem.getItem(index), element);
				}
			}			
		}
	}
	
    public boolean isExpandable(Object element) {
    	if (getContentProvider() instanceof ILazyTreeContentProvider) {
    		TreeItem treeItem = (TreeItem) internalExpand(element, false);
    		if (treeItem == null) {
    			return false;
    		}
    		virtualMaterializeItem(treeItem);
    		return treeItem.getItemCount() > 0;
    	}
    	return super.isExpandable(element);
    }
    protected Object getParentElement(Object element) {
    	if(!(element instanceof TreePath) && (getContentProvider() instanceof ILazyTreeContentProvider)) {
    		ILazyTreeContentProvider lazyTreeContentProvider = (ILazyTreeContentProvider) getContentProvider();
    		return lazyTreeContentProvider.getParent(element);
    	}