Bug 181061 [Viewers] JFace viewers performance issues in 3.3
A number of the JFace performance tests are red since I20060926-0800.
bundles/org.eclipse.jface/src/org/eclipse/jface/viewers/AbstractTreeViewer.java
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
	 *            optimising search for multiple elements that are sorted
	 *            themself.
	 * @param element
	 *            element to find position for.
	 * @param parentPath
	 *            the tree path for the element's parent or <code>null</code>