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/TreeViewer.java
*/
	public TreeViewer(Composite parent) {
		this(parent, SWT.MULTI | SWT.H_SCROLL | SWT.V_SCROLL | SWT.BORDER);
	}
	/**
	 * Creates a tree viewer on a newly-created tree control under the given
	 * parent. The tree control is created using the given SWT style bits. The
	 * viewer has no input, no content provider, a default label provider, no
	 * sorter, and no filters.
	 * 
	 * @param parent
	 *            the parent control
	 * @param style
	 *            the SWT style bits used to create the tree.
	 */
	public TreeViewer(Composite parent, int style) {
		this(new Tree(parent, style));
	}
	/**
	 * Creates a tree viewer on the given tree control. The viewer has no input,
	 * no content provider, a default label provider, no sorter, and no filters.
	 * 
	 * @param tree
	 *            the tree control
	 */
	public TreeViewer(Tree tree) {
		super();
		this.tree = tree;
		hookControl(tree);
		treeEditor = new TreeEditor(tree);