Bug 174701 [Viewers] ViewerRow should be reused instead of connected to the Item
Currently we create a ViewerRow ver every Item we create this can degrade performance, we should cache the row and reuse it
bundles/org.eclipse.jface/src/org/eclipse/jface/viewers/AbstractTreeViewer.java
* @param elementOrTreePath
	 * @return the parent element, or parent path, or <code>null</code>
	 * 
	 * @since 3.2
	 */
	protected Object getParentElement(Object elementOrTreePath) {
		if (elementOrTreePath instanceof TreePath) {
			TreePath treePath = (TreePath) elementOrTreePath;
			if (treePath.getSegmentCount() <= 1) {
				return null;
			}
			return (treePath).getParentPath();
		}
		IContentProvider cp = getContentProvider();
		if (cp instanceof ITreePathContentProvider) {
			ITreePathContentProvider tpcp = (ITreePathContentProvider) cp;
			TreePath[] paths = tpcp.getParents(elementOrTreePath);
			if (paths.length > 0) {
				if (paths[0].getSegmentCount() == 0) {
					return getInput();
				}
				return paths[0].getLastSegment();
			}
		}
		if (cp instanceof ITreeContentProvider) {
			ITreeContentProvider tcp = (ITreeContentProvider) cp;
			return tcp.getParent(elementOrTreePath);
		}
		return null;
	}