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
}
	}
	/**
	 * Returns a list of tree paths corresponding to expanded nodes in this
	 * viewer's tree, including currently hidden ones that are marked as
	 * expanded but are under a collapsed ancestor.
	 * <p>
	 * This method is typically used when preserving the interesting state of a
	 * viewer; <code>setExpandedElements</code> is used during the restore.
	 * </p>
	 * 
	 * @return the array of expanded tree paths
	 * @see #setExpandedElements
	 * 
	 * @since 3.2
	 */
	public TreePath[] getExpandedTreePaths() {
		ArrayList items = new ArrayList();
		internalCollectExpandedItems(items, getControl());
		ArrayList result = new ArrayList(items.size());
		for (Iterator it = items.iterator(); it.hasNext();) {
			Item item = (Item) it.next();
			TreePath treePath = getTreePathFromItem(item);
			if (treePath != null) {
				result.add(treePath);
			}
		}
		return (TreePath[]) result.toArray(new TreePath[items.size()]);
	}
	private boolean isTreePathContentProvider() {