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
/**
	 * Constant indicating that all levels of the tree should be expanded or
	 * collapsed.
	 * 
	 * @see #expandToLevel(int)
	 * @see #collapseToLevel(Object, int)
	 */
	public static final int ALL_LEVELS = -1;
	/**
	 * List of registered tree listeners (element type:
	 * <code>TreeListener</code>).
	 */
	private ListenerList treeListeners = new ListenerList();
	/**
	 * The level to which the tree is automatically expanded each time the
	 * viewer's input is changed (that is, by <code>setInput</code>). A value
	 * of 0 means that auto-expand is off.
	 * 
	 * @see #setAutoExpandLevel
	 */
	private int expandToLevel = 0;
	/**
	 * Safe runnable used to update an item.
	 */
	class UpdateItemSafeRunnable extends SafeRunnable {