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
/**
	 * Returns the number of columns of this viewer.
	 * <p><b>Subclasses should overwrite this method, which has a default
	 * implementation (returning 0) for API backwards compatility reasons</b></p>
	 *
	 * @return the number of columns
	 *
	 * @since 3.3
	 */
	protected int doGetColumnCount() {
		return 0;
	}
	
	
	/**
	 * This implementation of buildLabel handles tree paths as well as elements.
	 * 
	 * @param updateLabel
	 *            the ViewerLabel to collect the result in
	 * @param elementOrPath
	 *            the element or tree path for which a label should be built
	 * 
	 * @see org.eclipse.jface.viewers.StructuredViewer#buildLabel(org.eclipse.jface.viewers.ViewerLabel,
	 *      java.lang.Object)
	 */
	protected void buildLabel(ViewerLabel updateLabel, Object elementOrPath) {
		Object element;
		if (elementOrPath instanceof TreePath) {
			TreePath path = (TreePath) elementOrPath;
			IBaseLabelProvider provider = getLabelProvider();