Bug 156537 [Viewers] Virtual tree viewer does not populate with initial children
I20060830-1650 When a tree viewer is created with the SWT.Vitrual flag and uses an ILazyTreeContentProvider, the viewew does not populate with the initial children in the model. The method TreeViewer.createChildren(Widget) only updates existing items if the parent (root)element has been mapped to data, and does not query the content provider for the number of children it has. Attached is a sample plug-in showing the problem. The tree "model" looks like this: root one two three When the input is set to the viewer ("root") a call is made to "createChildren", but the content provider is never used.
bundles/org.eclipse.jface/src/org/eclipse/jface/viewers/AbstractTreeViewer.java
* widget and sorter. A <code>null</code> is returned if either the sorter
	 * is not a {@link TreePathViewerSorter} or if the parent widget is not an
	 * {@link Item} (i.e. is the root of the tree).
	 * 
	 * @param parent
	 *            the parent widget
	 * @param sorter
	 *            the sorter
	 * @return the tree path that should be used as the parent path for the
	 *         given widget and sorter
	 */
	private TreePath internalGetSorterParentPath(Widget parent,
			ViewerComparator comparator) {
		TreePath path;
		if (comparator instanceof TreePathViewerSorter
				&& parent instanceof Item) {
			Item item = (Item) parent;
			path = getTreePathFromItem(item);
		} else {
			path = null;
		}
		return path;
	}
	/**
	 * Compare the two elements using the given sorter. If the sorter is a
	 * {@link TreePathViewerSorter}, the provided tree path will be used. If
	 * the tree path is null and the sorter is a tree path sorter, then the
	 * elements are root elements
	 * 
	 * @param sorter