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
*            the widget to check
	 * @param index
	 *            the index of the widget
	 * @return Item or <code>null</code> if widget is not a type that can
	 *         contain items.
	 * 
	 * @throws ArrayIndexOutOfBoundsException
	 *             if the index is not valid.
	 * @since 3.1
	 */
	protected Item getChild(Widget widget, int index) {
		return getChildren(widget)[index];
	}
	/**
	 * Returns whether the given SWT item is expanded or collapsed.
	 * 
	 * @param item
	 *            the item
	 * @return <code>true</code> if the item is considered expanded and
	 *         <code>false</code> if collapsed
	 */
	protected abstract boolean getExpanded(Item item);
	/**
	 * Returns a list of elements corresponding to expanded nodes in this
	 * viewer's tree, including currently hidden ones that are marked as
	 * expanded but are under a collapsed ancestor.
	 * <p>
	 * This method is typically used when preserving the interesting state of a
	 * viewer; <code>setExpandedElements</code> is used during the restore.
	 * </p>