Bug 172019 [Viewers] Plus sign doesn't disappear when using deferred content providers
3.3 M4 Use a tree viewer with a content provider using IDeferredWorkbenchAdapter and DeferredTreeContentManager. When fetchDeferredChildren is call and no elements are reported to the element collector the plus sign of the node doesn't disappear. This work without problems under Windows and Mac/OS (e.g. the plus sign disappears).
bundles/org.eclipse.jface/src/org/eclipse/jface/viewers/AbstractTreeViewer.java
* if there is no next item.
	 * 
	 * @param item
	 *            the item
	 * @param includeChildren
	 *            <code>true</code> if the children are considered in
	 *            determining which item is next, and <code>false</code> if
	 *            subtrees are ignored
	 * @return the next item, or <code>null</code> if none
	 */
	protected Item getNextItem(Item item, boolean includeChildren) {
		if (item == null) {
			return null;
		}
		if (includeChildren && getExpanded(item)) {
			Item[] children = getItems(item);
			if (children != null && children.length > 0) {
				return children[0];
			}
		}
		
		
		Item parent = getParentItem(item);
		if (parent == null) {
			return null;
		}
		Item[] siblings = getItems(parent);
		if (siblings != null) {
			if (siblings.length <= 1) {
				return getNextItem(parent, false);