Bug 238299 [Viewers] Collapse All before expanding class/array suppresses display of all but first child node
bundles/org.eclipse.jface/src/org/eclipse/jface/viewers/AbstractTreeViewer.java
}
	/**
	 * See if element is the data of one of the elements in items.
	 *
	 * @param items
	 * @param element
	 * @return <code>true</code> if the element matches.
	 */
	private boolean itemExists(Item[] items, Object element) {
		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