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
*            the element
	 */
	public void remove(Object elementsOrTreePaths) {
		remove(new Object[] { elementsOrTreePaths });
	}
	/**
	 * Removes all items from the given control.
	 * 
	 * @param control
	 *            the control
	 */
	protected abstract void removeAll(Control control);
	/**
	 * Removes a listener for expand and collapse events in this viewer. Has no
	 * affect if an identical listener is not registered.
	 * 
	 * @param listener
	 *            a tree viewer listener
	 */
	public void removeTreeListener(ITreeViewerListener listener) {
		treeListeners.remove(listener);
	}
	/**
	 * This implementation of reveal() reveals the given element or tree path.
	 */
	public void reveal(Object elementOrTreePath) {
		Assert.isNotNull(elementOrTreePath);
		Widget w = internalExpand(elementOrTreePath, true);
		if (w instanceof Item) {
			showItem((Item) w);