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
if (usingElementMap()) {
			Widget[] existingItems = findItems(element);
			
			if (existingItems.length == 0) {
				return false;
			} else if (existingItems.length == 1) {
				if (items.length > 0 && existingItems[0] instanceof Item) {
					Item existingItem = (Item) existingItems[0];
					return getParentItem(existingItem) == getParentItem(items[0]);
				}
			}
		}
		for (int i = 0; i < items.length; i++) {
			if (items[i].getData().equals(element)) {
				return true;
			}
		}
		return false;
	}
	/**
	 * Returns the index where the item should be inserted. It uses sorter to
	 * determine the correct position, if sorter is not assigned, returns the
	 * index of the element after the last.
	 * 
	 * @param items
	 *            the items to search
	 * @param comparator
	 *            The comparator to use.
	 * @param lastInsertion
	 *            the start index to start search for position from this allows