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 the rightmost visible descendent of the given item. Returns the
	 * item itself if it has no children.
	 * 
	 * @param item
	 *            the item to compute the descendent of
	 * @return the rightmost visible descendent or the item iself if it has no
	 *         children
	 */
	private Item rightMostVisibleDescendent(Item item) {
		Item[] children = getItems(item);
		if (getExpanded(item) && children != null && children.length > 0) {
			return rightMostVisibleDescendent(children[children.length - 1]);
		}
		return item;
	}
	
	public Item scrollDown(int x, int y) {
		Item current = getItem(x, y);
		if (current != null) {
			Item next = getNextItem(current, true);
			showItem(next == null ? current : next);
			return next;
		}
		return null;
	}
	
	public Item scrollUp(int x, int y) {