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 SWT item
	 * @param element
	 *            the element
	 */
	protected void doUpdateItem(final Item item, Object element) {
		if (item.isDisposed()) {
			unmapElement(element, item);
			return;
		}
		int columnCount = doGetColumnCount();
		if (columnCount == 0)
			columnCount = 1;
		for (int column = 0; column < columnCount; column++) {
			ViewerColumn columnViewer = getViewerColumn(column);
			columnViewer.refresh(updateCell(getViewerRowFromItem(item),
					column));
			
			
			if (item.isDisposed()) {
				unmapElement(element, item);
				return;
			}
		}
	}
	
	/**
	 * Returns <code>true</code> if the given list and array of items refer to
	 * the same model elements. Order is unimportant.
	 * <p>
	 * This method is not intended to be overridden by subclasses.