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
* 
	 * @return the array of expanded elements
	 * @see #setExpandedElements
	 */
	public Object[] getExpandedElements() {
		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();
			Object data = item.getData();
			if (data != null) {
				result.add(data);
			}
		}
		return result.toArray();
	}
	/**
	 * Returns whether the node corresponding to the given element or tree path
	 * is expanded or collapsed.
	 * 
	 * @param elementOrTreePath
	 *            the element
	 * @return <code>true</code> if the node is expanded, and
	 *         <code>false</code> if collapsed
	 */
	public boolean getExpandedState(Object elementOrTreePath) {
		Assert.isNotNull(elementOrTreePath);
		Widget item = internalGetWidgetToSelect(elementOrTreePath);
		if (item instanceof Item) {